Programs & Examples On #Pmap

Android Material and appcompat Manifest merger failed

Just remove the dependancy

    implementation ''

Quoting From Material Guidelines

If you don’t want to switch over to the new androidx and packages yet, you can use Material Components via the dependency.

Note: You should not use the and in your app at the same time.

Just removing this dependency works fine

    implementation ''

Here is complete dependencies example

    dependencies {
       implementation fileTree(dir: 'libs', include: ['*.jar'])
       implementation ''
       implementation ''
       testImplementation 'junit:junit:4.12'
       androidTestImplementation ''
       androidTestImplementation ''

Warnings Your Apk Is Using Permissions That Require A Privacy Policy: (android.permission.READ_PHONE_STATE)

You should drop android.permission.READ_PHONE_STATE permission. Add this to your manifest file:

    tools:node="remove" />

How to fix: "You need to use a Theme.AppCompat theme (or descendant) with this activity"

Your application has an AppCompat theme


But, you overwrote the Activity (which extends AppCompatActivity) with a theme that isn't descendant of an AppCompat theme

<activity android:name=".MainActivity"
    android:theme="@android:style/Theme.NoTitleBar.Fullscreen" >

You could define your own fullscreen theme like so (notice AppCompat in the parent=)

<style name="AppFullScreenTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowActionBar">false</item>
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowContentOverlay">@null</item>

Then set that on the Activity.

<activity android:name=".MainActivity"
    android:theme="@style/AppFullScreenTheme" >

Note: There might be an AppCompat theme that's already full screen, but don't know immediately

Firebase cloud messaging notification not received by device

I faced the same problem but I had still had some debris in my manifest from the old GCM. When I took the following permission out of my manifest it fixed the error.

Notification Icon with the new Firebase Cloud Messaging system

Thought I would add an answer to this one, since my problem was simple but hard to notice. In particular I had copy/pasted an existing meta-data element when creating my, which used an android:value tag to specify its value. This will not work for the notification icon, and once I changed it to android:resource everything worked as expected.

How to remove title bar from the android activity?

Add in activity


and add your style.xml file with the following two lines:

<item name="windowActionBar">false</item>
<item name="windowNoTitle">true</item>

Manifest Merger failed with multiple errors in Android Studio

If you're using multiple manifestPlaceholder items in your build.gradle file, you must add them as array elements, instead of separate items.

For example, this will cause a build error or compile error: "java.lang.RuntimeException: Manifest merger failed with multiple errors":

android {
    defaultConfig {
        manifestPlaceholders = [myKey1: "myValue1"]
        manifestPlaceholders = [myKey2: "myValue2"] // Error!

This will fix the error:

android {
    defaultConfig {
        manifestPlaceholders = [myKey1: "myValue1", myKey2: "myValue2"]

ActivityCompat.requestPermissions not showing dialog box

For me the error was in the manifest: the permission was in uppercase. Android Studio suggest me the permissions in uppercase. I don't care about that and it took me two hours to fixe this problem.

The right syntaxe for permission is
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

android : Error converting byte to dex

For me was very easy. Just add:

//noinspection GradleDependency,GradleCompatible implementation ''

... and the magic happens.

READ_EXTERNAL_STORAGE permission for Android

You have two solutions for your problem. The quick one is to lower targetApi to 22 (build.gradle file). Second is to use new and wonderful ask-for-permission model:

if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE)
        != PackageManager.PERMISSION_GRANTED) {

    // Should we show an explanation?
    if (shouldShowRequestPermissionRationale(
            Manifest.permission.READ_EXTERNAL_STORAGE)) {
        // Explain to the user why we need to read the contacts

    requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},

    // app-defined int constant that should be quite unique


Sniplet found here:

Solutions 2: If it does not work try this:

    && ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},



and then in callback

public void onRequestPermissionsResult(final int requestCode, @NonNull final String[] permissions, @NonNull final int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == REQUEST_PERMISSION) {
    if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        // Permission granted.
    } else {
        // User refused to grant permission.

that is from comments. thanks

Android "gps requires ACCESS_FINE_LOCATION" error, even though my manifest file contains this

CAUSE: "Beginning in Android 6.0 (API level 23), users grant permissions to apps while the app is running, not when they install the app." In this case, "ACCESS_FINE_LOCATION" is a "dangerous permission and for that reason, you get this 'java.lang.SecurityException: "gps" location provider requires ACCESS_FINE_LOCATION permission.' error (

SOLUTION: Implementing the code provided at under the "Request the permissions you need" and "Handle the permissions request response" headings.

Execution failed for task 'app:mergeDebugResources' Crunching Cruncher....png failed

The Crunching process is the image preparation process, which means something is wrong with your image files. In my case I had a PNG file which was not really a PNG file.

My solution:

I converted all my images to PNG running a super simple Python script from within the image folder, so in total all you need to do is:

  1. In order to install the PIL library, run: pip install pillow

  2. Save the below Python code in a .py file within your images folder you want to convert.

  3. Adjust the from_format, to_format variables in the script to whatever you need.

  4. Run script: python

    import os
    from PIL import Image
    from_format = (".jpg", ".png", ".bmp")
    to_format = "png"
    for fn in os.listdir('.'):
         if os.path.isfile(fn) and fn.lower().endswith(from_format):
            print "Converting File: %s" % fn
            im =
  '.')[0] + '.' + to_format, to_format.upper())

And if you want read more about the Image module:

Android Studio drawable folders

If you don't see a drawable folder for the DPI that you need, you can create it yourself. There's nothing magical about it; it's just a folder which needs to have the correct name.

Mipmaps vs. drawable folders

The mipmap folders are for placing your app/launcher icons (which are shown on the homescreen) in only. Any other drawable assets you use should be placed in the relevant drawable folders as before.

According to this Google blogpost:

It’s best practice to place your app icons in mipmap- folders (not the drawable- folders) because they are used at resolutions different from the device’s current density.

When referencing the mipmap- folders ensure you are using the following reference:


The reason they use a different density is that some launchers actually display the icons larger than they were intended. Because of this, they use the next size up.

Mipmap drawables for icons

The Android implementation of mipmaps in 4.3 is exactly the technique from 1983 explained in the Wikipedia article :)

Each bitmap image of the mipmap set is a downsized duplicate of the main texture, but at a certain reduced level of detail. Although the main texture would still be used when the view is sufficient to render it in full detail, the renderer will switch to a suitable mipmap image (...) when the texture is viewed from a distance or at a small size.

Although this is described as a technique for 3D graphics (as it mentions "viewing from a distance"), it applies just as well to 2D (translated as "drawn is a smaller space", i.e. "downscaled").

For a concrete Android example, imagine you have a View with a certain background drawable (in particular, a BitmapDrawable). You now use an animation to scale it to 0.15 of its original size. Normally, this would require downscaling the background bitmap for each frame. This "extreme" downscaling, however, may produce visual artifacts.

You can, however, provide a mipmap, which means that the image is already pre-rendered for a few specific scales (let's say 1.0, 0.5, and 0.25). Whenever the animation "crosses" the 0.5 threshold, instead of continuing to downscale the original, 1.0-sized image, it will switch to the 0.5 image and downscale it, which should provide a better result. And so forth as the animation continues.

This is a bit theoretical, since it's actually done by the renderer. According to the source of the Bitmap class, it's just a hint, and the renderer may or may not honor it.

 * Set a hint for the renderer responsible for drawing this bitmap
 * indicating that it should attempt to use mipmaps when this bitmap
 * is drawn scaled down.
 * If you know that you are going to draw this bitmap at less than
 * 50% of its original size, you may be able to obtain a higher
 * quality by turning this property on.
 * Note that if the renderer respects this hint it might have to
 * allocate extra memory to hold the mipmap levels for this bitmap.
 * This property is only a suggestion that can be ignored by the
 * renderer. It is not guaranteed to have any effect.
 * @param hasMipMap indicates whether the renderer should attempt
 *                  to use mipmaps
 * @see #hasMipMap()
public final void setHasMipMap(boolean hasMipMap) {
    nativeSetHasMipMap(mNativeBitmap, hasMipMap);

I'm not quite sure why this would be especially suitable for application icons, though. Although Android on tablets, as well as some launchers (e.g. GEL), request an icon "one density higher" to show it bigger, this is supposed to be done using the regular mechanism (i.e. drawable-xxxhdpi, &c).

How to obtain the query string from the current URL with JavaScript?

Convert that into array then split with '?'

var url= 'http://localhost/PMApp/temp.htm?ProjectID=462';

url.split('?')[1];     //ProjectID=462

Get key from a HashMap using the value

  • If you need only that, simply use put(100, "one"). Note that the key is the first argument, and the value is the 2nd.
  • If you need to be able to get by both the key and the value, use BiMap (from guava)

Namespace not recognized (even though it is there)

In my case i had copied a classlibrary, and not changed the "Assembly Name" in the project properties, so one DLL was overwriting the other...

&& (AND) and || (OR) in IF statements

This goes back to the basic difference between & and &&, | and ||

BTW you perform the same tasks many times. Not sure if efficiency is an issue. You could remove some of the duplication.

Z z2 = partialHits.get(req_nr).get(z); // assuming a value cannout be null.
Z z3 = tmpmap.get(z); // assuming z3 cannot be null.
if(z2 == null || z2 < z3){   
    partialHits.get(z).put(z, z3);   

ArithmeticException: "Non-terminating decimal expansion; no exact representable decimal result"

Answer for BigDecimal throws ArithmeticException

public static void main(String[] args) {
        int age = 30;
        BigDecimal retireMentFund = new BigDecimal("10000.00");
        BigDecimal yearsInRetirement = new BigDecimal("20.00");
        String name = " Dennis";
        for ( int i = age; i <=65; i++){
            recalculate(retireMentFund,new BigDecimal("0.10"));
        BigDecimal monthlyPension =   retireMentFund.divide(
                yearsInRetirement.divide(new BigDecimal("12"), new MathContext(2, RoundingMode.CEILING)), new MathContext(2, RoundingMode.CEILING));      
        System.out.println(name+ " will have £" + monthlyPension +" per month for retirement");
public static void recalculate (BigDecimal fundAmount, BigDecimal rate){
        fundAmount.multiply(rate.add(new BigDecimal("1.00")));

Add MathContext object in your divide method call and adjust precision and rounding mode. This should fix your problem

JAXB Exception: Class not known to this context

I had this error because I registered the wrong class in this line of code:

JAXBContext context = JAXBContext.newInstance(MyRootXmlClass.class);

Optional args in MATLAB functions

There are a few different options on how to do this. The most basic is to use varargin, and then use nargin, size etc. to determine whether the optional arguments have been passed to the function.

% Function that takes two arguments, X & Y, followed by a variable 
% number of additional arguments
function varlist(X,Y,varargin)
   fprintf('Total number of inputs = %d\n',nargin);

   nVarargs = length(varargin);
   fprintf('Inputs in varargin(%d):\n',nVarargs)
   for k = 1:nVarargs
      fprintf('   %d\n', varargin{k})

A little more elegant looking solution is to use the inputParser class to define all the arguments expected by your function, both required and optional. inputParser also lets you perform type checking on all arguments.

Floating Point Exception C++ Why and what is it?

A "floating point number" is how computers usually represent numbers that are not integers -- basically, a number with a decimal point. In C++ you declare them with float instead of int. A floating point exception is an error that occurs when you try to do something impossible with a floating point number, such as divide by zero.

Replace all whitespace with a line break/paragraph mark to make a word list

  1. option 1

    echo $(cat testfile)
  2. Option 2

    tr ' ' '\n' < testfile

How can I delete all cookies with JavaScript?

Why do you use new Date instead of a static UTC string?

    function clearListCookies(){
    var cookies = document.cookie.split(";");
        for (var i = 0; i < cookies.length; i++){   
            var spcook =  cookies[i].split("=");
            document.cookie = spcook[0] + "=;expires=Thu, 21 Sep 1979 00:00:01 UTC;";                                

Trim last character from a string

The another example of trimming last character from a string:

string outputText = inputText.Remove(inputText.Length - 1, 1);

You can put it into an extension method and prevent it from null string, etc.

How to empty a Heroku database

If you are logged in from the console, this will do the job in the latest heroku toolbelt,

heroku pg:reset --confirm database-name

Android Studio: “Execution failed for task ':app:mergeDebugResources'” if project is created on drive C:

For developers who live in Iran, Just rebuild while offline. You're done! (it's related to sanctions!)

Java, "Variable name" cannot be resolved to a variable

public void setHoursWorked(){
    hoursWorked = hours;

You haven't defined hours inside that method. hours is not passed in as a parameter, it's not declared as a variable, and it's not being used as a class member, so you get that error.

The name 'ConfigurationManager' does not exist in the current context

I have gotten a better solution for the issue configurationmanager does not exist in the current context.

To a read connection string from web.config we need to use ConfigurationManager class and its method. If you want to use you need to add namespace using System.Configuration;

Though you used this namespace, when you try to use the ConfigurationManager class then the system shows an error “configurationmanager does not exist in the current context”. To solve this Problem:


Writelines writes lines without newline, Just fills the file

writelines() does not add line separators. You can alter the list of strings by using map() to add a new \n (line break) at the end of each string.

items = ['abc', '123', '!@#']
items = map(lambda x: x + '\n', items)

Git pull command from different user

Was looking for the solution of a similar problem. Thanks to the answer provided by Davlet and Cupcake I was able to solve my problem.

Posting this answer here since I think this is the intended question

So I guess generally the problem that people like me face is what to do when a repo is cloned by another user on a server and that user is no longer associated with the repo.

How to pull from the repo without using the credentials of the old user ?

You edit the .git/config file of your repo.

and change

url = https://<old-username>


url = https://<new-username>

After saving the changes, from now onwards git pull will pull data while using credentials of the new user.

I hope this helps anyone with a similar problem

running a command as a super user from a python script

The safest way to do this is to prompt for the password beforehand and then pipe it into the command. Prompting for the password will avoid having the password saved anywhere in your code and it also won't show up in your bash history. Here's an example:

from getpass import getpass
from subprocess import Popen, PIPE

password = getpass("Please enter your password: ")
# sudo requires the flag '-S' in order to take input from stdin
proc = Popen("sudo -S apach2ctl restart".split(), stdin=PIPE, stdout=PIPE, stderr=PIPE)
# Popen only accepts byte-arrays so you must encode the string

How do I split a multi-line string into multiple lines?

Like the others said:

inputString.split('\n')  # --> ['Line 1', 'Line 2', 'Line 3']

This is identical to the above, but the string module's functions are deprecated and should be avoided:

import string
string.split(inputString, '\n')  # --> ['Line 1', 'Line 2', 'Line 3']

Alternatively, if you want each line to include the break sequence (CR,LF,CRLF), use the splitlines method with a True argument:

inputString.splitlines(True)  # --> ['Line 1\n', 'Line 2\n', 'Line 3']

Styling twitter bootstrap buttons

In Twitter Bootstrap bootstrap 3.0.0, Twitter button is flat. You can customize it from Button color, border radious etc.

Also you can find the HTML code and others functionality

Bootstrap 2.3.2 button is gradient but 3.0.0 ( new release ) flat and looks more cool.

and also you can find to customize the entire bootstrap looks and style form this resources:

ORA-01830: date format picture ends before converting entire input string / Select sum where date query

You can try as follows it works for me

select * from nm_admission where trunc(entry_timestamp) = to_date('09-SEP-2018','DD-MM-YY');


select * from nm_admission where trunc(entry_timestamp) = '09-SEP-2018';

You can also try using to_char but remember to_char is too expensive

select * from nm_admission where to_char(entry_timestamp) = to_date('09-SEP-2018','DD-MM-YY');

The TRUNC(17-SEP-2018 08:30:11) will give 17-SEP-2018 00:00:00 as a result, you can compare the only date portion independently and time portion will skip.

C# Macro definitions in Preprocessor

No, C# does not support preprocessor macros like C. Visual Studio on the other hand has snippets. Visual Studio's snippets are a feature of the IDE and are expanded in the editor rather than replaced in the code on compilation by a preprocessor.

With Spring can I make an optional path variable?

Check this Spring 3 WebMVC - Optional Path Variables. It shows an article of making an extension to AntPathMatcher to enable optional path variables and might be of help. All credits to Sebastian Herold for posting the article.

Replace preg_replace() e modifier with preg_replace_callback

You shouldn't use flag e (or eval in general).

You can also use T-Regx library


undefined reference to boost::system::system_category() when compiling

in my case, adding -lboost_system was not enough, it still could not find it in my custom build environment. I had to use the advice at Get rid of "gcc - /usr/bin/ld: warning lib not found" and change my ./configure command to:

./configure CXXFLAGS="-I$HOME/include" LDFLAGS="-L$HOME/lib -Wl,-rpath-link,$HOME/lib" --with-boost-libdir=$HOME/lib --prefix=$HOME

for more details see Boost 1.51 : "error: could not link against boost_thread !"

DLL References in Visual C++

You need to do a couple of things to use the library:

  1. Make sure that you have both the *.lib and the *.dll from the library you want to use. If you don't have the *.lib, skip #2

  2. Put a reference to the *.lib in the project. Right click the project name in the Solution Explorer and then select Configuration Properties->Linker->Input and put the name of the lib in the Additional Dependencies property.

  3. You have to make sure that VS can find the lib you just added so you have to go to the Tools menu and select Options... Then under Projects and Solutions select VC++ Directories,edit Library Directory option. From within here you can set the directory that contains your new lib by selecting the 'Library Files' in the 'Show Directories For:' drop down box. Just add the path to your lib file in the list of directories. If you dont have a lib you can omit this, but while your here you will also need to set the directory which contains your header files as well under the 'Include Files'. Do it the same way you added the lib.

After doing this you should be good to go and can use your library. If you dont have a lib file you can still use the dll by importing it yourself. During your applications startup you can explicitly load the dll by calling LoadLibrary (see: for more info)



Remember to use #include < Foo.h > as opposed to #include "foo.h". The former searches the include path. The latter uses the local project files.

Flask Value error view function did not return a response

The following does not return a response:

You must return anything like return afunction() or return 'a string'.

This can solve the issue

passing JSON data to a Spring MVC controller

You can stringify the JSON Object with JSON.stringify(jsonObject) and receive it on controller as String.

In the Controller, you can use the javax.json to convert and manipulate this.

Download and add the .jar to the project libs and import the JsonObject.

To create an json object, you can use

JsonObjectBuilder job = Json.createObjectBuilder();
job.add("header1", foo1);
job.add("header2", foo2);
JsonObject json =;

To read it from String, you can use

JsonReader jr = Json.createReader(new StringReader(jsonString));
JsonObject json = jsonReader.readObject();

Matplotlib different size subplots

Another way is to use the subplots function and pass the width ratio with gridspec_kw:

import numpy as np
import matplotlib.pyplot as plt 

# generate some data
x = np.arange(0, 10, 0.2)
y = np.sin(x)

# plot it
f, (a0, a1) = plt.subplots(1, 2, gridspec_kw={'width_ratios': [3, 1]})
a0.plot(x, y)
a1.plot(y, x)


cvc-elt.1: Cannot find the declaration of element 'MyElement'

I got this same error working in Eclipse with Maven with the additional information

schema_reference.4: Failed to read schema document '', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.

This was after copying in a new controller and it's interface from a Thymeleaf example. Honestly, no matter how careful I am I still am at a loss to understand how one is expected to figure this out. On a (lucky) guess I right clicked the project, clicked Maven and Update Project which cleared up the issue.

Trying to get PyCharm to work, keep getting "No Python interpreter selected"

This situation occurred to me when I uninstalled a method and tried to reinstall it. My very same interpreter, which worked before, suddenly stopped working. And this error occurred.

I tried restarting my PC, reinstalling Pycharm, invalidating caches, nothing worked.

Then I went here to reinstall the interpreter:

When you install it, there's an option to fix the python.exe interpreter. Click that. My IDE went back to normal working conditions.

How to send characters in PuTTY serial communication only when pressing enter?

The settings you need are "Local echo" and "Line editing" under the "Terminal" category on the left.

To get the characters to display on the screen as you enter them, set "Local echo" to "Force on".

To get the terminal to not send the command until you press Enter, set "Local line editing" to "Force on".

PuTTY Line discipline options


From the PuTTY User Manual (Found by clicking on the "Help" button in PuTTY):

4.3.8 ‘Local echo’

With local echo disabled, characters you type into the PuTTY window are not echoed in the window by PuTTY. They are simply sent to the server. (The server might choose to echo them back to you; this can't be controlled from the PuTTY control panel.)

Some types of session need local echo, and many do not. In its default mode, PuTTY will automatically attempt to deduce whether or not local echo is appropriate for the session you are working in. If you find it has made the wrong decision, you can use this configuration option to override its choice: you can force local echo to be turned on, or force it to be turned off, instead of relying on the automatic detection.

4.3.9 ‘Local line editing’ Normally, every character you type into the PuTTY window is sent immediately to the server the moment you type it.

If you enable local line editing, this changes. PuTTY will let you edit a whole line at a time locally, and the line will only be sent to the server when you press Return. If you make a mistake, you can use the Backspace key to correct it before you press Return, and the server will never see the mistake.

Since it is hard to edit a line locally without being able to see it, local line editing is mostly used in conjunction with local echo (section 4.3.8). This makes it ideal for use in raw mode or when connecting to MUDs or talkers. (Although some more advanced MUDs do occasionally turn local line editing on and turn local echo off, in order to accept a password from the user.)

Some types of session need local line editing, and many do not. In its default mode, PuTTY will automatically attempt to deduce whether or not local line editing is appropriate for the session you are working in. If you find it has made the wrong decision, you can use this configuration option to override its choice: you can force local line editing to be turned on, or force it to be turned off, instead of relying on the automatic detection.

Putty sometimes makes wrong choices when "Auto" is enabled for these options because it tries to detect the connection configuration. Applied to serial line, this is a bit trickier to do.

How to import other Python files?

In case the module you want to import is not in a sub-directory, then try the following and run from the deepest common parent directory:

Directory Structure:


In, append path of client to sys.path:

import os, sys, inspect

from module.file import MyClass
instance = MyClass()

Optional (If you load e.g. configs) (Inspect seems to be the most robust one for my use cases)

# Get dirname from inspect module
filename = inspect.getframeinfo(inspect.currentframe()).filename
dirname = os.path.dirname(os.path.abspath(filename))
MY_CONFIG = os.path.join(dirname, "subpath/config.json")


user@host:/path/to/common_dir$ python3 application/

This solution works for me in cli, as well as PyCharm. Connection refused

Hope my experience may be useful to someone. I faced the problem with the same exception stack trace and I couldn't understand what the issue was. The Database server which I was trying to connect was running and the port was open and was accepting connections.

The issue was with internet connection. The internet connection that I was using was not allowed to connect to the corresponding server. When I changed the connection details, the issue got resolved.

How to avoid the "Windows Defender SmartScreen prevented an unrecognized app from starting warning"

If you have a standard code signing certificate, some time will be needed for your application to build trust. Microsoft affirms that an Extended Validation (EV) Code Signing Certificate allows us to skip this period of trust-building. According to Microsoft, extended validation certificates allow the developer to immediately establish a reputation with SmartScreen. Otherwise, the users will see a warning like "Windows Defender SmartScreen prevented an unrecognized app from starting. Running this app might put your PC at risk.", with the two buttons: "Run anyway" and "Don't run".

Another Microsoft resource states the following (quote): "Although not required, programs signed by an EV code signing certificate can immediately establish a reputation with SmartScreen reputation services even if no prior reputation exists for that file or publisher. EV code signing certificates also have a unique identifier which makes it easier to maintain reputation across certificate renewals."

My experience is as follows. Since 2005, we have been using regular (non-EV) code signing certificates to sign .MSI, .EXE and .DLL files with time stamps, and there has never been a problem with SmartScreen until 2018, when there was just one case when it took 3 days for a beta version of our application to build trust since we have released it to beta testers, and it was in the middle of certificate validity period. I don't know what SmartScreen might not like in that specific version of our application, but there have been no SmartScreen complaints since then. Therefore, if your certificate is a non-EV, it is a signed application (such as an .MSI file) that will build trust over time, not a certificate. For example, a certificate can be issued a few months ago and used to sign many files, but for each signed file you publish, it may take a few days for SmartScreen to stop complaining about the file after publishing, as was in our case in 2018.

As a conclusion, to avoid the warning completely, i.e. prevent it from happening even suddenly, you need an Extended Validation (EV) code signing certificate.

PHPMailer character encoding issues

To avoid problems of character encoding in sending emails using the class PHPMailer we can configure it to send it with UTF-8 character encoding using the "CharSet" parameter, as we can see in the following Php code:

$mail = new PHPMailer();
$mail->From = '[email protected]';
$mail->FromName = 'Mi nombre';
$mail->AddAddress('[email protected]');
$mail->Subject = 'Prueba';
$mail->Body = '';

// Active condition utf-8
$mail->CharSet = 'UTF-8';

// Send mail

How to enter a formula into a cell using VBA?

You aren't building your formula right.

Worksheets("EmployeeCosts").Range("B" & var1a).Formula =  "=SUM(H5:H" & var1a & ")"

This does the same as the following lines do:

Dim myFormula As String
myFormula = "=SUM(H5:H"
myFormula = myFormula & var1a
myformula = myformula & ")"

which is what you are trying to do.

Also, you want to have the = at the beginning of the formala.

Excel VBA to Export Selected Sheets to PDF

this is what i came up with as i was having issues with @asp8811 answer(maybe my own difficulties)

' this will do the put the first 2 sheets in a pdf ' Note each ws should be controlled with page breaks for printing which is a bit fiddly ' this will explicitly put the pdf in the current dir

Sub luxation2()
    Dim Filename As String
    Filename = "temp201"

Dim shtAry()
ReDim shtAry(1) ' this is an array of length 2
For i = 1 To 2
shtAry(i - 1) = Sheets(i).Name
Debug.Print Sheets(i).Name
Next i
Debug.Print ThisWorkbook.Path & "\"

    ActiveSheet.ExportAsFixedFormat xlTypePDF, ThisWorkbook.Path & "/" & Filename & ".pdf", , , False

End Sub

How to make a simple popup box in Visual C#?

System.Windows.Forms.MessageBox.Show("My message here");

Make sure the System.Windows.Forms assembly is referenced your project.

HTTP Request in Swift with POST method

@IBAction func btn_LogIn(sender: AnyObject) {

    let request = NSMutableURLRequest(URL: NSURL(string: "")!)
    request.HTTPMethod = "POST"
    let postString = "email: [email protected] & password: testtest"
    request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding)
    let task = NSURLSession.sharedSession().dataTaskWithRequest(request){data, response, error in
        guard error == nil && data != nil else{
        if let httpStatus = response as? NSHTTPURLResponse where httpStatus.statusCode != 200{
            print("statusCode should be 200, but is \(httpStatus.statusCode)")
            print("response = \(response)")
        let responseString = String(data: data!, encoding: NSUTF8StringEncoding)
        print("responseString = \(responseString)")

How to center form in bootstrap 3

<div class="col-md-4 offset-md-4"> 
put your form here

Init function in javascript and how it works

Its is called immediatly invoking function expression (IIFE). Mainly associated with the JavaScript closure concept. Main use is to run the function before the global variable changed, so that the expected behaviour of code can be retained.

Is there a way to reduce the size of the git folder?

I'm not sure what you want. First of all, of course each time you commit/push the directory is going to get a little larger, since it has to store each of those additional commits.

However, probably you want git gc which will "cleanup unnecessary files and optimize the local repository" (manual page).

Another possibly relevant command is git clean which will delete untracked files from your tree (manual page).

Is null reference possible?

If your intention was to find a way to represent null in an enumeration of singleton objects, then it's a bad idea to (de)reference null (it C++11, nullptr).

Why not declare static singleton object that represents NULL within the class as follows and add a cast-to-pointer operator that returns nullptr ?

Edit: Corrected several mistypes and added if-statement in main() to test for the cast-to-pointer operator actually working (which I forgot to.. my bad) - March 10 2015 -

// Error.h
class Error {
  static Error& NOT_FOUND;
  static Error& UNKNOWN;
  static Error& NONE; // singleton object that represents null

  static vector<shared_ptr<Error>> _instances;
  static Error& NewInstance(const string& name, bool isNull = false);

  bool _isNull;
  Error(const string& name, bool isNull = false) : _name(name), _isNull(isNull) {};
  Error() {};
  Error(const Error& src) {};
  Error& operator=(const Error& src) {};

  operator Error*() { return _isNull ? nullptr : this; }

// Error.cpp
vector<shared_ptr<Error>> Error::_instances;
Error& Error::NewInstance(const string& name, bool isNull = false)
  shared_ptr<Error> pNewInst(new Error(name, isNull)).
  return *pNewInst.get();

Error& Error::NOT_FOUND = Error::NewInstance("NOT_FOUND");
//Error& Error::NOT_FOUND = Error::NewInstance("UNKNOWN"); Edit: fixed
//Error& Error::NOT_FOUND = Error::NewInstance("NONE", true); Edit: fixed
Error& Error::UNKNOWN = Error::NewInstance("UNKNOWN");
Error& Error::NONE = Error::NewInstance("NONE");

// Main.cpp
#include "Error.h"

Error& getError() {
  return Error::UNKNOWN;

// Edit: To see the overload of "Error*()" in Error.h actually working
Error& getErrorNone() {
  return Error::NONE;

int main(void) {
  if(getError() != Error::NONE) {
    return EXIT_FAILURE;

  // Edit: To see the overload of "Error*()" in Error.h actually working
  if(getErrorNone() != nullptr) {
    return EXIT_FAILURE;

What does it mean to "call" a function in Python?

when you invoke a function , it is termed 'calling' a function . For eg , suppose you've defined a function that finds the average of two numbers like this-

def avgg(a,b) :
        return (a+b)/2;

now, to call the function , you do like this .

print x

value of x will be 5 .

Total number of items defined in an enum

From the previous answers just adding code sample.

 class Program
        static void Main(string[] args)
            int enumlen = Enum.GetNames(typeof(myenum)).Length;
        public enum myenum

Throwing exceptions from constructors

Throwing an exception is the best way of dealing with constructor failure. You should particularly avoid half-constructing an object and then relying on users of your class to detect construction failure by testing flag variables of some sort.

On a related point, the fact that you have several different exception types for dealing with mutex errors worries me slightly. Inheritance is a great tool, but it can be over-used. In this case I would probably prefer a single MutexError exception, possibly containing an informative error message.

Create a temporary table in MySQL with an index from a select

Did find the answer on my own. My problem was, that i use two temporary tables for a join and create the second one out of the first one. But the Index was not copied during creation...

KEY(tmpid), INDEX(tmpid))
SELECT * FROM tblLivecheck_copy WHERE tblLivecheck_copy.devId = did;

SELECT * FROM tmpLivecheck;

... solved my problem.


Stop fixed position at footer

If your elements are glitching this is probably because when you change the position to relative the Y position of the footer increases which tries to send the item back to fixed which creates a loop. You can avoid this by setting two different cases when scrolling up and down. You don't even need to reference the fixed element, just the footer, and window size.

const footer = document.querySelector('footer');
document.addEventListener("scroll", checkScroll);

let prevY = window.scrollY + window.innerHeight;
function checkScroll() {
  let footerTop = getRectTop(footer) + window.scrollY;
  let windowBottomY = window.scrollY + window.innerHeight;
  if (prevY < windowBottomY) {  // Scroll Down
    if (windowBottomY > footerTop)
      setScrolledToFooter(true) // using React state. Change class or change style in JS.
  } else { // Scroll Up
    if (windowBottomY <= footerTop)
  prevY = windowBottomY

function getRectTop(el) {
  var rect = el.getBoundingClientRect();

and the position of the element in the style object as follows:

position: scrolledToFooter ? 'relative' : 'fixed'

CSS: How to position two elements on top of each other, without specifying a height?

Actually this is possible without position absolute and specifying any height. All You need to do, is use display: grid on parent element and put descendants, into the same row and column.

Please check example below, based on Your HTML. I added only <span> and some colors, so You can see the result.

You can also easily change z-index each of descendant elements, to manipulate its visibility (which one should be on top).

  display: grid;_x000D_
.layer1, .layer2{_x000D_
  grid-column: 1;_x000D_
  grid-row: 1;_x000D_
.layer1 span{_x000D_
  color: #fff;_x000D_
  background: #000cf6;_x000D_
  background: rgba(255, 0, 0, 0.4);_x000D_
<div class="container_row">_x000D_
    <div class="layer1">_x000D_
        <span>Lorem ipsum...<br>Test test</span>_x000D_
    <div class="layer2">_x000D_
        More lorem ipsum..._x000D_
<div class="container_row">_x000D_
    ...same HTML as above. This one should never overlap the .container_row above._x000D_

Erasing elements from a vector

  1. You can iterate using the index access,

  2. To avoid O(n^2) complexity you can use two indices, i - current testing index, j - index to store next item and at the end of the cycle new size of the vector.


void erase(std::vector<int>& v, int num)
  size_t j = 0;
  for (size_t i = 0; i < v.size(); ++i) {
    if (v[i] != num) v[j++] = v[i];
  // trim vector to new size

In such case you have no invalidating of iterators, complexity is O(n), and code is very concise and you don't need to write some helper classes, although in some case using helper classes can benefit in more flexible code.

This code does not use erase method, but solves your task.

Using pure stl you can do this in the following way (this is similar to the Motti's answer):

#include <algorithm>

void erase(std::vector<int>& v, int num) {
    vector<int>::iterator it = remove(v.begin(), v.end(), num);
    v.erase(it, v.end());

Check to see if python script is running

try this:

#/usr/bin/env python
import os, sys, atexit

    # Set PID file
    def set_pid_file():
        pid = str(os.getpid())
        f = open('', 'w')

    def goodby():
        pid = str('')

    # Place your code here

except KeyboardInterrupt:

Cleanest way to toggle a boolean variable in Java?

If you use Boolean NULL values and consider them false, try this:

static public boolean toggle(Boolean aBoolean) {
    if (aBoolean == null) return true;
    else return !aBoolean;

If you are not handing Boolean NULL values, try this:

static public boolean toggle(boolean aBoolean) {
   return !aBoolean;

These are the cleanest because they show the intent in the method signature, are easier to read compared to the ! operator, and can be easily debugged.


boolean bTrue = true
boolean bFalse = false
boolean bNull = null

toggle(bTrue) // == false
toggle(bFalse) // == true
toggle(bNull) // == true

Of course, if you use Groovy or a language that allows extension methods, you can register an extension and simply do:

Boolean b = false
b = b.toggle() // == true

Using 'starts with' selector on individual class names

While the top answer here is a workaround for the asker's particular case, if you're looking for a solution to actually using 'starts with' on individual class names:

You can use this custom jQuery selector, which I call :acp() for "A Class Prefix." Code is at the bottom of this post.

var test = $('div:acp("starting_text")');

This will select any and all <div> elements that have at least one class name beginning with the given string ("starting_text" in this example), regardless of whether that class is at the beginning or elsewhere in the class attribute strings.

<div id="1" class="apple orange lemon" />
<div id="2" class="orange applelemon banana" />
<div id="3" class="orange lemon apple" />
<div id="4" class="lemon orangeapple" />
<div id="5" class="lemon orange" />

var startsWithapp = $('div:acp("app")');

This will return elements 1, 2, and 3, but not 4 or 5.

Here's the declaration for the :acp custom selector, which you can put anywhere:

    $.expr[":"].acp = function(elem, index, m){
          var regString = '\\b' + m[3];
          var reg = new RegExp(regString, "g");
          return elem.className.match(reg);

I made this because I do a lot of GreaseMonkey hacking of websites on which I have no backend control, so I often need to find elements with class names that have dynamic suffixes. It's been very useful.

How to list the files in current directory?

Had a quick snoop around for this one, but this looks like it should work. I haven't tested it yet though.

    File f = new File("."); // current directory

    File[] files = f.listFiles();
    for (File file : files) {
        if (file.isDirectory()) {
        } else {
            System.out.print("     file:");

How can I write text on a HTML5 canvas element?

Yes of course you can write a text on canvas with ease, and you can set the font name, font size and font color. There are two method to build a text on Canvas, i.e. fillText() and strokeText(). fillText() method is used to make a text that can only be filled with color, whereas strokeText() is used to make a text that can only be given an outline color. So if we want to build a text that filled with color and have outline color, we must use both of them.

here the full example, how to write text on canvas :

<canvas id="Canvas01" width="400" height="200" style="border:2px solid #bbb; margin-left:10px; margin-top:10px;"></canvas>

  var canvas = document.getElementById('Canvas01');
  var ctx = canvas.getContext('2d');

  ctx.fillStyle= "red";
  ctx.font = "italic bold 35pt Tahoma";
  //syntax : .fillText("text", x, y)


Here the demo for this, and you can try your self for any modification:

How is Perl's @INC constructed? (aka What are all the ways of affecting where Perl modules are searched for?)

In addition to the locations listed above, the OS X version of Perl also has two more ways:

  1. The /Library/Perl/x.xx/AppendToPath file. Paths listed in this file are appended to @INC at runtime.

  2. The /Library/Perl/x.xx/PrependToPath file. Paths listed in this file are prepended to @INC at runtime.

How to put attributes via XElement

Add XAttribute in the constructor of the XElement, like

new XElement("Conn", new XAttribute("Server", comboBox1.Text));

You can also add multiple attributes or elements via the constructor

new XElement("Conn", new XAttribute("Server", comboBox1.Text), new XAttribute("Database", combobox2.Text));

or you can use the Add-Method of the XElement to add attributes

XElement element = new XElement("Conn");
XAttribute attribute = new XAttribute("Server", comboBox1.Text);

In java how to get substring from a string till a character c?

This could help:

public static String getCorporateID(String fileName) {

    String corporateId = null;

    try {
        corporateId = fileName.substring(0, fileName.indexOf("_"));
        // System.out.println(new Date() + ": " + "Corporate:
        // "+corporateId);
        return corporateId;
    } catch (Exception e) {
        corporateId = null;

    return corporateId;

What is the simplest way to write the contents of a StringBuilder to a text file in .NET 1.1?

StreamWriter is available for NET 1.1. and for the Compact framework. Just open the file and apply the ToString to your StringBuilder:

    StringBuilder sb = new StringBuilder();

    StreamWriter sw = new StreamWriter("\\hereIAm.txt", true);

Also, note that you say that you want to append debug messages to the file (like a log). In this case, the correct constructor for StreamWriter is the one that accepts an append boolean flag. If true then it tries to append to an existing file or create a new one if it doesn't exists.

@Html.DropDownListFor how to set default value

Like this:

@Html.DropDownListFor(model => model.Status, new List<SelectListItem> 
       { new SelectListItem{Text="Active", Value="True"},
         new SelectListItem{Text="Deactive", Value="False"}},"Select One")

If you want Active to be selected by default then use Selected property of SelectListItem:

@Html.DropDownListFor(model => model.Status, new List<SelectListItem> 
           { new SelectListItem{Text="Active", Value="True",Selected=true},
             new SelectListItem{Text="Deactive", Value="False"}},"Select One")

If using SelectList, then you have to use this overload and specify SelectListItem Value property which you want to set selected:

@Html.DropDownListFor(model => model.title, 
                     new SelectList(new List<SelectListItem>
      new SelectListItem { Text = "Active" , Value = "True"},
      new SelectListItem { Text = "InActive", Value = "False" }
    "Value", // property to be set as Value of dropdown item
    "Text",  // property to be used as text of dropdown item
    "True"), // value that should be set selected of dropdown
     new { @class = "form-control" })

What is the format for the PostgreSQL connection string / URL?


Multiple files upload (Array) with CodeIgniter 2.0

I recently work on it. Try this function:

 * @return array an array of your files uploaded.
private function _upload_files($field='userfile'){
    $files = array();
    foreach( $_FILES[$field] as $key => $all )
        foreach( $all as $i => $val )
            $files[$i][$key] = $val;

    $files_uploaded = array();
    for ($i=0; $i < count($files); $i++) { 
        $_FILES[$field] = $files[$i];
        if ($this->upload->do_upload($field))
            $files_uploaded[$i] = $this->upload->data($files);
            $files_uploaded[$i] = null;
    return $files_uploaded;

in your case:

<input type="file" multiple name="images[]" size="20" />


<input type="file" name="images[]">
<input type="file" name="images[]">
<input type="file" name="images[]">

in the controller:

public function do_upload(){
    $config['upload_path'] = './Images/';
    $config['allowed_types'] = 'gif|jpg|png';


    if ($_FILES['images']) {
        $images= $this->_upload_files('images');

Some basic reference from PHP manual: PHP file upload

Run batch file as a Windows service

There's a built in windows cmd to do this: sc create. Not as fancy as nssm, but you don't have to download an additional piece of software.

sc create "ServiceName" start= demand displayname= "DisplayName" binpath= [path to .bat file]


  • start=demand means you must start the service yourself
  • whitespace is required after =
  • I did encounter an error on service start that the service did not respond in a timely manner, but it was clear the service had run the .bat successfully. Haven't dug into this yet but this thread experienced the same thing and solved it using nssm to install the service.

How to run a Command Prompt command with Visual Basic code?

Here is an example:

Process.Start("CMD", "/C Pause")

/C  Carries out the command specified by string and then terminates
/K  Carries out the command specified by string but remains

And here is a extended function: (Notice the comment-lines using CMD commands.)

#Region " Run Process Function "

' [ Run Process Function ]
' // By Elektro H@cker
' Examples :
' MsgBox(Run_Process("Process.exe")) 
' MsgBox(Run_Process("Process.exe", "Arguments"))
' MsgBox(Run_Process("CMD.exe", "/C Dir /B", True))
' MsgBox(Run_Process("CMD.exe", "/C @Echo OFF & For /L %X in (0,1,50000) Do (Echo %X)", False, False))
' MsgBox(Run_Process("CMD.exe", "/C Dir /B /S %SYSTEMDRIVE%\*", , False, 500))
' If Run_Process("CMD.exe", "/C Dir /B", True).Contains("File.txt") Then MsgBox("File found")

Private Function Run_Process(ByVal Process_Name As String, _
                             Optional Process_Arguments As String = Nothing, _
                             Optional Read_Output As Boolean = False, _
                             Optional Process_Hide As Boolean = False, _
                             Optional Process_TimeOut As Integer = 999999999)

    ' Returns True if "Read_Output" argument is False and Process was finished OK
    ' Returns False if ExitCode is not "0"
    ' Returns Nothing if process can't be found or can't be started
    ' Returns "ErrorOutput" or "StandardOutput" (In that priority) if Read_Output argument is set to True.


        Dim My_Process As New Process()
        Dim My_Process_Info As New ProcessStartInfo()

        My_Process_Info.FileName = Process_Name ' Process filename
        My_Process_Info.Arguments = Process_Arguments ' Process arguments
        My_Process_Info.CreateNoWindow = Process_Hide ' Show or hide the process Window
        My_Process_Info.UseShellExecute = False ' Don't use system shell to execute the process
        My_Process_Info.RedirectStandardOutput = Read_Output '  Redirect (1) Output
        My_Process_Info.RedirectStandardError = Read_Output ' Redirect non (1) Output
        My_Process.EnableRaisingEvents = True ' Raise events
        My_Process.StartInfo = My_Process_Info
        My_Process.Start() ' Run the process NOW

        My_Process.WaitForExit(Process_TimeOut) ' Wait X ms to kill the process (Default value is 999999999 ms which is 277 Hours)

        Dim ERRORLEVEL = My_Process.ExitCode ' Stores the ExitCode of the process
        If Not ERRORLEVEL = 0 Then Return False ' Returns the Exitcode if is not 0

        If Read_Output = True Then
            Dim Process_ErrorOutput As String = My_Process.StandardOutput.ReadToEnd() ' Stores the Error Output (If any)
            Dim Process_StandardOutput As String = My_Process.StandardOutput.ReadToEnd() ' Stores the Standard Output (If any)
            ' Return output by priority
            If Process_ErrorOutput IsNot Nothing Then Return Process_ErrorOutput ' Returns the ErrorOutput (if any)
            If Process_StandardOutput IsNot Nothing Then Return Process_StandardOutput ' Returns the StandardOutput (if any)
        End If

    Catch ex As Exception
        Return Nothing ' Returns nothing if the process can't be found or started.
    End Try

    Return True ' Returns True if Read_Output argument is set to False and the process finished without errors.

End Function

#End Region

Make child visible outside an overflow:hidden parent

Neither of the posted answers worked for me. Setting position: absolute for the child element did work however.

How can I use MS Visual Studio for Android Development?

Much has changed since this question was asked. Visual Studio 2013 with update 4 and Visual Studio 2015 now have integrated tools for Apache Cordova and you can run them on a Visual Studio emulator for Android.

'App not Installed' Error on Android

I had a similar situation.I was able to install app in debug mode using USB but not a signed version. I was able to install signed version on other phone, but not on my device. Numerous reasons and solutions did not help me. But one direction I got from a solution "uninstall for all users". What I did is to again install app in debug mode using USB connection, go to app details and "uninstall for all users" from right top 3 dots - to remove debug version. This looks like cleared all kinds of references. I usually do a normal uninstall.

Now I am able to get signed APK on the device and install and its success.

Error running android: Gradle project sync failed. Please fix your project and try again

I got this error going from Gradle 3.5.3 to 5.4.1 (Android Studio prompted and I clicked "Upgrade".)

Gradle proceeded to upgrade but yielded some errors such as:

ERROR: The Android Gradle plugin supports only Crashlytics Gradle plugin version 1.25.4 and higher.
The following dependencies do not satisfy the required version:
root project 'Android%20App' ->
Update plugins
Affected Modules: app

INFO: API 'variant.getExternalNativeBuildTasks()' is obsolete and has been replaced with 'variant.getExternalNativeBuildProviders()'.
It will be removed at the end of 2019.
For more information, see
To determine what is calling variant.getExternalNativeBuildTasks(), use -Pandroid.debug.obsoleteApi=true on the command line to display more information.
Affected Modules: app

INFO: The specified Android SDK Build Tools version (27.0.3) is ignored, as it is below the minimum supported version (28.0.3) for Android Gradle Plugin 3.5.3.
Android SDK Build Tools 28.0.3 will be used.
To suppress this warning, remove "buildToolsVersion '27.0.3'" from your build.gradle file, as each version of the Android Gradle Plugin now has a default version of the build tools.
Install Build Tools 28.0.3, update version in build file and sync project
Affected Modules: app

The thing that fixed it was opening Settings --> Appearance & Behavior --> System Settings --> Android SDK and I then selected some recent versions of Android SDK like 8, 9, and 10. (I had only had 5.1, 6.0, and Android N Preview installed.)

Once that's installed, I had to modify my build.gradle file for my Module: app

  • Removed buildToolsVersion '27.0.3'

Then I clicked the "Sync Project with Gradle Files" button on the toolbar. The Sync output window offered an option to "Update Plugins" and once I clicked through that everything seemed to work. For good measure I again clicked "Sync Project with Gradle Files" followed by Build --> Clean Project, and finally I was able to run my project again.

Form submit with AJAX passing form data to PHP without page refresh

In event handling, pass the object of event to the function and then add statement i.e. event.preventDefault();

This will pass data to webpage without refreshing it.

zsh compinit: insecure directories

This was the only thing that worked for me from Thanks!

  $ cd /usr/local/share/
  $ sudo chmod -R 755 zsh
  $ sudo chown -R root:staff zsh

Running Windows batch file commands asynchronously

There's a third (and potentially much easier) option. If you want to spin up multiple instances of a single program, using a Unix-style command processor like Xargs or GNU Parallel can make that a fairly straightforward process.

There's a win32 Xargs clone called PPX2 that makes this fairly straightforward.

For instance, if you wanted to transcode a directory of video files, you could run the command:

dir /b *.mpg |ppx2 -P 4 -I {} -L 1 ffmpeg.exe -i "{}" -quality:v 1 "{}.mp4"

Picking this apart, dir /b *.mpg grabs a list of .mpg files in my current directory, the | operator pipes this list into ppx2, which then builds a series of commands to be executed in parallel; 4 at a time, as specified here by the -P 4 operator. The -L 1 operator tells ppx2 to only send one line of our directory listing to ffmpeg at a time.

After that, you just write your command line (ffmpeg.exe -i "{}" -quality:v 1 "{}.mp4"), and {} gets automatically substituted for each line of your directory listing.

It's not universally applicable to every case, but is a whole lot easier than using the batch file workarounds detailed above. Of course, if you're not dealing with a list of files, you could also pipe the contents of a textfile or any other program into the input of pxx2.

ASP.NET MVC3 Razor - Html.ActionLink style

Reviving an old question because it seems to appear at the top of search results.

I wanted to retain transition effects while still being able to style the actionlink so I came up with this solution.

  1. I wrapped the action link with a div that would contain the parent style:
<div class="parent-style-one">
      @Html.ActionLink("Homepage", "Home", "Home")
  1. Next I create the CSS for the div, this will be the parent css and will be inherited by the child elements such as the action link.
  .parent-style-one {
     /* your styles here */
  1. Because all an action link is, is an element when broken down as html so you just need to target that element in your css selection:
  .parent-style-one a {
     text-decoration: none;
  1. For transition effects I did this:
  .parent-style-one a:hover {
        text-decoration: underline;
        -webkit-transition-duration: 1.1s; /* Safari */
        transition-duration: 1.1s;         

This way I only target the child elements of the div in this case the action link and still be able to apply transition effects.

Is it possible to define more than one function per file in MATLAB, and access them from outside that file?

I define multiple functions in one .m file with Octave and then use the command from within the .m file where I need to make use of the functions from that file:


Not sure if this is available with Matlab.

octave:8> help source
'source' is a built-in function

 -- Built-in Function:  source (FILE)
     Parse and execute the contents of FILE.  This is equivalent to
     executing commands from a script file, but without requiring the
     file to be named `FILE.m'.

XML Error: There are multiple root elements

You can do it without modifying the XML stream: Tell the XmlReader to not be so picky. Setting the XmlReaderSettings.ConformanceLevel to ConformanceLevel.Fragment will let the parser ignore the fact that there is no root node.

        XmlReaderSettings settings = new XmlReaderSettings();
        settings.ConformanceLevel = ConformanceLevel.Fragment;
        using (XmlReader reader = XmlReader.Create(tr,settings))

Now you can parse something like this (which is an real time XML stream, where it is impossible to wrap with a node).

  <payload type='80'>7d1300786a0000000bf9458b0518000000000000000000000000000000000c0c030306001b</payload>
  <payload type='80'>fd1260780912ff3028fea5ffc0387d640fa550f40fbdf7afffe001fff8200fff00f0bf0e000042201421100224ff40312300111400004f000000e0c0fbd1e0000f10e0fccc2ff0000f0fe00f00f0eed00f11e10d010021420401</payload>
  <payload type='80'>fd126078ad11fc4015fefdf5b042ff1010223500000000000000003007ff00f20e0f01000e0000dc0f01000f000000000000004f000000f104ff001000210f000013010000c6da000000680ffa807800200000000d00c0f0</payload>

Using with React components

First argument in update method is SyntheticEvent object that contains common properties and methods to any event, it is not reference to React component where there is property props.

if you need pass argument to update method you can do it like this

onClick={ (e) => this.props.onClick(e, 'home', 'Home') }

and get these arguments inside update method

update(e, space, txt){
   console.log(, space, txt);

Example gives you the native DOMNode, then you need to use the regular DOM APIs to access attributes. For instance getAttribute or dataset

  onClick={ this.props.onClick } 

onClick(e) {


REST API error code 500 handling

You suggested "Catching any unexpected errors and return some error code signaling "unexpected situation" " but couldn't find an appropriate error code.

Guess what: That's what 5xx is there for.

PHP, pass array through POST

The first comment answers this.

<form ....>
<input name="person[0][first_name]" value="john" />
<input name="person[0][last_name]" value="smith" />
<input name="person[1][first_name]" value="jane" />
<input name="person[1][last_name]" value="jones" />


array (
0 => array('first_name'=>'john','last_name'=>'smith'),
1 => array('first_name'=>'jane','last_name'=>'jones'),

The name tag can work as an array.

Read line by line in bash script

xargs is the most flexible solution for splitting output into command arguments.

It is also very human readable and easy to use due to its simple parameterisation.

Format is xargs -n $NUMLINES mycommand.

For example, to echo each individual line in a file /tmp/tmp.txt you'd do:

cat /tmp/tmp.txt | xargs -n 1 echo

Or to diff each successive pair of files listed as lines in a file of the above name you'd do:

cat /tmp/tmp.txt | xargs -n 2 diff

The -n 2 instructs xargs to consume and pass as separate arguments two lines of what you've piped into it at a time.

You can tailor xargs to split on delimiters besides carriage return/newline.

Use man xargs and google to find out more about the power of this versatile utility.

How to append rows in a pandas dataframe in a for loop?

There are 2 reasons you may append rows in a loop, 1. add to an existing df, and 2. create a new df.

to create a new df, I think its well documented that you should either create your data as a list and then create the data frame:

cols = ['c1', 'c2', 'c3']
lst = []
for a in range(2):
    lst.append([1, 2, 3])
df1 = pd.DataFrame(lst, columns=cols)
   c1  c2  c3
0   1   2   3
1   1   2   3

OR, Create the dataframe with an index and then add to it

cols = ['c1', 'c2', 'c3']
df2 = pd.DataFrame(columns=cols, index=range(2))
for a in range(2):
    df2.loc[a].c1 = 4
    df2.loc[a].c2 = 5
    df2.loc[a].c3 = 6
  c1 c2 c3
0  4  5  6
1  4  5  6

If you want to add to an existing dataframe, you could use either method above and then append the df's together (with or without the index):

df3 = df2.append(df1, ignore_index=True)
  c1 c2 c3
0  4  5  6
1  4  5  6
2  1  2  3
3  1  2  3

Or, you can also create a list of dictionary entries and append those as in the answer above.

lst_dict = []
for a in range(2):
    lst_dict.append({'c1':2, 'c2':2, 'c3': 3})
df4 = df1.append(lst_dict)
   c1  c2  c3
0   1   2   3
1   1   2   3
0   2   2   3
1   2   2   3

Using the dict(zip(cols, vals)))

lst_dict = []
for a in range(2):
    vals = [7, 8, 9]
    lst_dict.append(dict(zip(cols, vals)))
df5 = df1.append(lst_dict)

Linker error: "linker input file unused because linking not done", undefined reference to a function in that file

I think you are confused about how the compiler puts things together. When you use -c flag, i.e. no linking is done, the input is C++ code, and the output is object code. The .o files thus don't mix with -c, and compiler warns you about that. Symbols from object file are not moved to other object files like that.

All object files should be on the final linker invocation, which is not the case here, so linker (called via g++ front-end) complains about missing symbols.

Here's a small example (calling g++ explicitly for clarity):

PROG ?= myprog
OBJS = worker.o main.o

all: $(PROG)

        g++ -Wall -pedantic -ggdb -O2 -c -o $@ $<

$(PROG): $(OBJS)
        g++ -Wall -pedantic -ggdb -O2 -o $@ $(OBJS)

There's also makedepend utility that comes with X11 - helps a lot with source code dependencies. You might also want to look at the -M gcc option for building make rules.

How can I convert a comma-separated string to an array?

The split() method is used to split a string into an array of substrings, and returns the new array.

var array = string.split(',');

Assign result of dynamic sql to variable

Sample to execute an SQL string within the stored procedure:

(I'm using this to compare the number of entries on each table as first check for a regression test, within a cursor loop)

select @SqlQuery1 = N'select @CountResult1 = (select isnull(count(*),0) from ' + @DatabaseFirst+'.dbo.'+@ObjectName + ')'

execute sp_executesql    @SqlQuery1 , N'@CountResult1 int OUTPUT',     @CountResult1 = @CountResult1 output;

How to delete a folder with files using Java

As mentioned, Java isn't able to delete a folder that contains files, so first delete the files and then the folder.

Here's a simple example to do this:


// First, remove files from into the folder 

// Then, remove the folder


FileUtils.forceDelete(new File(destination));

Best practice for localization and globalization of strings and labels

When you’re faced with a problem to solve (and frankly, who isn’t these days?), the basic strategy usually taken by we computer people is called “divide and conquer.” It goes like this:

  • Conceptualize the specific problem as a set of smaller sub-problems.
  • Solve each smaller problem.
  • Combine the results into a solution of the specific problem.

But “divide and conquer” is not the only possible strategy. We can also take a more generalist approach:

  • Conceptualize the specific problem as a special case of a more general problem.
  • Somehow solve the general problem.
  • Adapt the solution of the general problem to the specific problem.

- Eric Lippert

I believe many solutions already exist for this problem in server-side languages such as ASP.Net/C#.

I've outlined some of the major aspects of the problem

  • Issue: We need to load data only for the desired language

    Solution: For this purpose we save data to a separate files for each language

ex.,, res.en.js, res.js(for default language)

  • Issue: Resource files for each page should be separated so we only get the data we need

    Solution: We can use some tools that already exist like

  • Issue: We need a key/value pair structure to save our data

    Solution: I suggest a javascript object instead of string/string air. We can benefit from the intellisense from an IDE

  • Issue: General members should be stored in a public file and all pages should access them

    Solution: For this purpose I make a folder in the root of web application called Global_Resources and a folder to store global file for each sub folders we named it 'Local_Resources'

  • Issue: Each subsystems/subfolders/modules member should override the Global_Resources members on their scope

    Solution: I considered a file for each

Application Structure


The corresponding code for the files:


var res = {
    Create : "Create",
    Update : "Save Changes",
    Delete : "Delete"


var res = {
    Create : "créer",
    Update : "Enregistrer les modifications",
    Delete : "effacer"

The resource file for the desired language should be loaded on the page selected from Global_Resource - This should be the first file that is loaded on all the pages.


res.Name = "Name";
res.UserName = "UserName";
res.Password = "Password";


res.Name = "nom";
res.UserName = "Nom d'utilisateur";
res.Password = "Mot de passe";


// Override res.Create on Global_Resources/default.js
res.Create = "Create User"; 


// Override Global_Resources/
res.Create = "Créer un utilisateur";

manager.js file (this file should be load last)

res.lang = "fr";

var globalResourcePath = "Global_Resources";
var resourceFiles = [];

var currentFile = globalResourcePath + "\\default" + res.lang + ".js" ;

    currentFile = globalResourcePath + "\\default.js" ;
if(!IsFileExist(currentFile)) throw new Exception("File Not Found");


// Push parent folder on folder into folder
foreach(var folder in parent folder of current page)
    currentFile = folder + "\\Local_Resource\\default." + res.lang + ".js";

        currentFile = folder + "\\Local_Resource\\default.js";
    if(!IsExist(currentFile)) throw new Exception("File Not Found");


for(int i = 0; i < resourceFiles.length; i++) { Load.js(resourceFiles[i]); }

// Get current page name
var pageNameWithoutExtension = "SomePage";

currentFile = currentPageFolderPath + pageNameWithoutExtension + res.lang + ".js" ;

    currentFile = currentPageFolderPath + pageNameWithoutExtension + ".js" ;
if(!IsExist(currentFile)) throw new Exception("File Not Found");

Hope it helps :)

How to split data into trainset and testset randomly?

from sklearn.model_selection import train_test_split
import numpy

with open("datafile.txt", "rb") as f:
   data ='\n')
   data = numpy.array(data)  #convert array to numpy type array

   x_train ,x_test = train_test_split(data,test_size=0.5)       #test_size=0.5(whole_data)

Hibernate problem - "Use of @OneToMany or @ManyToMany targeting an unmapped class"

Your annotations look fine. Here are the things to check:

  • make sure the annotation is javax.persistence.Entity, and not org.hibernate.annotations.Entity. The former makes the entity detectable. The latter is just an addition.

  • if you are manually listing your entities (in persistence.xml, in hibernate.cfg.xml, or when configuring your session factory), then make sure you have also listed the ScopeTopic entity

  • make sure you don't have multiple ScopeTopic classes in different packages, and you've imported the wrong one.

Oracle insert from select into table with more columns

Just add in the '0' in your select.

INSERT INTO table_name (a,b,c,d)
       other_table.a AS a,
       other_table.b AS b,
       other_table.c AS c,
       '0' AS d
    FROM other_table

Counting inversions in an array

another Python solution

def inv_cnt(a):
n = len(a)
if n==1:
    return a,0
left = a[0:n//2] # should be smaller
left,cnt1 = inv_cnt(left)    
right = a[n//2:] # should be larger
right, cnt2 = inv_cnt(right)

cnt = 0    
i_left = i_right = i_a = 0
while i_a < n:
    if (i_right>=len(right)) or (i_left < len(left) and left[i_left] <= right[i_right]):
        a[i_a] = left[i_left]
        i_left += 1
        a[i_a] = right[i_right]
        i_right += 1              
        if i_left < len(left):
            cnt += len(left) - i_left        
    i_a += 1    

return (a, (cnt1 + cnt2 + cnt))

Can't bind to 'ngIf' since it isn't a known property of 'div'

Instead of [ngIf] you should use *ngIf like this:

<div *ngIf="isAuth" id="sidebar">

Refreshing all the pivot tables in my excel workbook with a macro

This VBA code will refresh all pivot tables/charts in the workbook.

Sub RefreshAllPivotTables()

Dim PT As PivotTable
Dim WS As Worksheet

    For Each WS In ThisWorkbook.Worksheets

        For Each PT In WS.PivotTables
        Next PT

    Next WS

End Sub

Another non-programatic option is:

  • Right click on each pivot table
  • Select Table options
  • Tick the 'Refresh on open' option.
  • Click on the OK button

This will refresh the pivot table each time the workbook is opened.

Index of element in NumPy array

You can use the function numpy.nonzero(), or the nonzero() method of an array

import numpy as np

A = np.array([[2,4],
index= np.nonzero(A>1)


(array([0, 1]), array([1, 0]))

First array in output depicts the row index and second array depicts the corresponding column index.

Accessing value inside nested dictionaries

No, those are nested dictionaries, so that is the only real way (you could use get() but it's the same thing in essence). However, there is an alternative. Instead of having nested dictionaries, you can use a tuple as a key instead:

tempDict = {("ONE", "TWO", "THREE"): 10}
tempDict["ONE", "TWO", "THREE"]

This does have a disadvantage, there is no (easy and fast) way of getting all of the elements of "TWO" for example, but if that doesn't matter, this could be a good solution.

SQL Server table creation date query

For SQL Server 2000:

FROM     sysobjects so JOIN sysusers su
ON       so.uid = su.uid
WHERE    xtype='U'

Sorting Directory.GetFiles()

Just an idea. I like to find an easy way out and try re use already available resources. if I were to sort files I would've just create a process and make syscal to "DIR [x:\Folders\SubFolders*.*] /s /b /on" and capture the output.

With system's DIR command you can sort by :

/O          List by files in sorted order.
sortorder    N  By name (alphabetic)       S  By size (smallest first)
             E  By extension (alphabetic)  D  By date/time (oldest first)
             G  Group directories first    -  Prefix to reverse order

The /S switch includes sub folders

I AM NOT SURE IF D = By Date/Time is using LastModifiedDate or FileCreateDate. But if the needed sort order is already built-in in the DIR command, I will get that by calling syscall. And it's FAST. I am just the lazy guy ;)

After a little googling I found switch to sort by particular date/time:-

/t [[:]TimeField] : Specifies which time field to display or use for sorting. The following list describes each of the values you can use for TimeField. 

Value Description 
c : Creation
a : Last access
w : Last written

Check/Uncheck checkbox with JavaScript

to check:

document.getElementById("id-of-checkbox").checked = true;

to uncheck:

document.getElementById("id-of-checkbox").checked = false;

How can I specify my .keystore file with Spring Boot and Tomcat?

Starting with Spring Boot 1.2, you can configure SSL using or application.yml. Here's an example for

server.port = 8443
server.ssl.key-store = classpath:keystore.jks
server.ssl.key-store-password = secret
server.ssl.key-password = another-secret

Same thing with application.yml:

  port: 8443
    key-store: classpath:keystore.jks
    key-store-password: secret
    key-password: another-secret

Here's a link to the current reference documentation.

How do I insert an image in an activity with android studio?

since you followed the tutorial, I presume you have a screen that says Hello World.

that means you have some code in your layout xml that looks like this

    android:text="@string/hello_world" />

you want to display an image, so instead of TextView you want to have ImageView. and instead of a text attribute you want an src attribute, that links to your drawable resource


Box-Shadow on the left side of the element only

box-shadow: -15px 0px 17px -7px rgba(0,0,0,0.75);

The first px value is the "Horizontal Length" set to -15px to position the shadow towards the left, the next px value is set to 0 so the shadow top and bottom is centred to minimise the top and bottom shadow.

The third value(17px) is known as the blur radius. The higher the number, the more blurred the shadow will be. And then last px value -7px is The spread radius, a positive value increases the size of the shadow, a negative value decreases the size of the shadow, at -7px it keeps the shadow from appearing above and below the item.

reference: CSS Box Shadow Property

The difference between the 'Local System' account and the 'Network Service' account?

Since there is so much confusion about functionality of standard service accounts, I'll try to give a quick run down.

First the actual accounts:

  • LocalService account (preferred)

    A limited service account that is very similar to Network Service and meant to run standard least-privileged services. However, unlike Network Service it accesses the network as an Anonymous user.

    • Name: NT AUTHORITY\LocalService
    • the account has no password (any password information you provide is ignored)
    • HKCU represents the LocalService user account
    • has minimal privileges on the local computer
    • presents anonymous credentials on the network
    • SID: S-1-5-19
    • has its own profile under the HKEY_USERS registry key (HKEY_USERS\S-1-5-19)


  • NetworkService account

    Limited service account that is meant to run standard privileged services. This account is far more limited than Local System (or even Administrator) but still has the right to access the network as the machine (see caveat above).

    • NT AUTHORITY\NetworkService
    • the account has no password (any password information you provide is ignored)
    • HKCU represents the NetworkService user account
    • has minimal privileges on the local computer
    • presents the computer's credentials (e.g. MANGO$) to remote servers
    • SID: S-1-5-20
    • has its own profile under the HKEY_USERS registry key (HKEY_USERS\S-1-5-20)
    • If trying to schedule a task using it, enter NETWORK SERVICE into the Select User or Group dialog


  • LocalSystem account (dangerous, don't use!)

    Completely trusted account, more so than the administrator account. There is nothing on a single box that this account cannot do, and it has the right to access the network as the machine (this requires Active Directory and granting the machine account permissions to something)

    • Name: .\LocalSystem (can also use LocalSystem or ComputerName\LocalSystem)
    • the account has no password (any password information you provide is ignored)
    • SID: S-1-5-18
    • does not have any profile of its own (HKCU represents the default user)
    • has extensive privileges on the local computer
    • presents the computer's credentials (e.g. MANGO$) to remote servers


Above when talking about accessing the network, this refers solely to SPNEGO (Negotiate), NTLM and Kerberos and not to any other authentication mechanism. For example, processing running as LocalService can still access the internet.

The general issue with running as a standard out of the box account is that if you modify any of the default permissions you're expanding the set of things everything running as that account can do. So if you grant DBO to a database, not only can your service running as Local Service or Network Service access that database but everything else running as those accounts can too. If every developer does this the computer will have a service account that has permissions to do practically anything (more specifically the superset of all of the different additional privileges granted to that account).

It is always preferable from a security perspective to run as your own service account that has precisely the permissions you need to do what your service does and nothing else. However, the cost of this approach is setting up your service account, and managing the password. It's a balancing act that each application needs to manage.

In your specific case, the issue that you are probably seeing is that the the DCOM or COM+ activation is limited to a given set of accounts. In Windows XP SP2, Windows Server 2003, and above the Activation permission was restricted significantly. You should use the Component Services MMC snapin to examine your specific COM object and see the activation permissions. If you're not accessing anything on the network as the machine account you should seriously consider using Local Service (not Local System which is basically the operating system).

In Windows Server 2003 you cannot run a scheduled task as

  • NT_AUTHORITY\LocalService (aka the Local Service account), or
  • NT AUTHORITY\NetworkService (aka the Network Service account).

That capability only was added with Task Scheduler 2.0, which only exists in Windows Vista/Windows Server 2008 and newer.

A service running as NetworkService presents the machine credentials on the network. This means that if your computer was called mango, it would present as the machine account MANGO$:

enter image description here

Advantages of using display:inline-block vs float:left in CSS

You can find answer in depth here.

But in general with float you need to be aware and take care of the surrounding elements and inline-block simple way to line elements.


How to turn off word wrapping in HTML?

If you want a HTML only solution, we can just use the pre tag. It defines "preformatted text" which means that it does not format word-wrapping. Here is a quick example to explain:

div {
    width: 200px;
    height: 200px;
    padding: 20px;
    background: #adf;
pre {
    width: 200px;
    height: 200px;
    padding: 20px;
    font: inherit;
    background: #fda;
<div>Look at this, this text is very neat, isn't it? But it's not quite what we want, though, is it? This text shouldn't be here! It should be all the way over there! What can we do?</div>
<pre>The pre tag has come to the rescue! Yay! However, we apologise in advance for any horizontal scrollbars that may be caused. If you need support, please raise a support ticket.</pre>

Spring Security exclude url patterns in security annotation configurartion

Where are you configuring your authenticated URL pattern(s)? I only see one uri in your code.

Do you have multiple configure(HttpSecurity) methods or just one? It looks like you need all your URIs in the one method.

I have a site which requires authentication to access everything so I want to protect /*. However in order to authenticate I obviously want to not protect /login. I also have static assets I'd like to allow access to (so I can make the login page pretty) and a healthcheck page that shouldn't require auth.

In addition I have a resource, /admin, which requires higher privledges than the rest of the site.

The following is working for me.

protected void configure(HttpSecurity http) throws Exception {



NOTE: This is a first match wins so you may need to play with the order. For example, I originally had /** first:


Which caused the site to continually redirect all requests for /login back to /login. Likewise I had /admin/** last:


Which resulted in my unprivledged test user "guest" having access to the admin interface (yikes!)

MVC: How to Return a String as JSON

Yeah that's it without no further issues, to avoid raw string json this is it.

    public ActionResult GetJson()
        var json = System.IO.File.ReadAllText(

        return new ContentResult
            Content = json,
            ContentType = "application/json",
            ContentEncoding = Encoding.UTF8

NOTE: please note that method return type of JsonResult is not working for me, since JsonResult and ContentResult both inherit ActionResult but there is no relationship between them.

Eslint: How to disable "unexpected console statement" in Node.js?

2018 October,

just do:

// tslint:disable-next-line:no-console

the anothers answer with

// eslint-disable-next-line no-console

does not work !

How to grant remote access permissions to mysql server for user?

This worked for me. But there was a strange problem that even I tryed first those it didnt affect. I updated phpmyadmin page and got it somehow working.

If you need access to local-xampp-mysql. You can go to xampp-shell -> opening command prompt.

Then mysql -uroot -p --port=3306 or mysql -uroot -p (if there is password set). After that you can grant those acces from mysql shell page (also can work from localhost/phpmyadmin).

Just adding these if somebody find this topic and having beginner problems.

How to create a file in Linux from terminal window?

Depending on what you want the file to contain:

  • touch /path/to/file for an empty file
  • somecommand > /path/to/file for a file containing the output of some command.

      eg: grep --help > randomtext.txt
          echo "This is some text" > randomtext.txt
  • nano /path/to/file or vi /path/to/file (or any other editor emacs,gedit etc)
    It either opens the existing one for editing or creates & opens the empty file to enter, if it doesn't exist

Create the file using cat

$ cat > myfile.txt

Now, just type whatever you want in the file:

Hello World!

CTRL-D to save and exit

There are several possible solutions:

Create an empty file

touch file


echo -n > file

printf '' > file

The echo version will work only if your version of echo supports the -n switch to suppress newlines. This is a non-standard addition. The other examples will all work in a POSIX shell.

Create a file containing a newline and nothing else

echo '' > file

printf '\n' > file

This is a valid "text file" because it ends in a newline.

Write text into a file

"$EDITOR" file

echo 'text' > file

cat > file <<END \

printf 'text\n' > file

These are equivalent. The $EDITOR command assumes that you have an interactive text editor defined in the EDITOR environment variable and that you interactively enter equivalent text. The cat version presumes a literal newline after the \ and after each other line. Other than that these will all work in a POSIX shell.

Of course there are many other methods of writing and creating files, too.

Internet Explorer 11- issue with security certificate error prompt

If you updated Internet Explorer and began having technical problems, you can use the Compatibility View feature to emulate a previous version of Internet Explorer.

For instructions, see the section below that corresponds with your version. To find your version number, click Help > About Internet Explorer. Internet Explorer 11

To edit the Compatibility View list:

Open the desktop, and then tap or click the Internet Explorer icon on the taskbar.
Tap or click the Tools button (Image), and then tap or click Compatibility View settings.
To remove a website:
Click the website(s) where you would like to turn off Compatibility View, clicking Remove after each one.
To add a website:
Under Add this website, enter the website(s) where you would like to turn on Compatibility View, clicking Add after each one.

How can I call a method in Objective-C?

syntax is of objective c is

returnObj = [object functionName: parameters];

Where object is the object which has the method you're calling. If you're calling it from the same object, you'll use 'self'. This tutorial might help you out in learning Obj-C.

In your case it is simply

[self score];

If you want to pass a parameter then it is like that

- (void)score(int x) {
    // some code

and I have tried to call it in an other method like this:

- (void)score2 {
    [self score:x];

How to get data from observable in angular2

Angular is based on observable instead of promise base as of angularjs 1.x, so when we try to get data using http it returns observable instead of promise, like you did

 return this.http
      .map(res => res.json());

then to get data and show on view we have to convert it into desired form using RxJs functions like .map() function and .subscribe()

.map() is used to convert the observable (received from http request)to any form like .json(), .text() as stated in Angular's official website,

.subscribe() is used to subscribe those observable response and ton put into some variable so from which we display it into the view

this.myService.getConfig().subscribe(res => {
   console.log(res); = res;

Mongodb service won't start

it probably might be due to the mongod.lock file, but if the error persists even after deleting it check the paths in mongo.conf; it might be a simple issue such as the configured log Path or dbPath is not there (check the paths in mongo/conf/mongod.conf and check whether they exists, sometimes mongo cannot in its own create directory structures therefore you might have to create those directories manually before starting mongod).

JavaScript string newline character?

A practical observation... In my NodeJS script I have the following function:

function writeToLogFile (message) {
    fs.appendFile('myserverlog.txt', Date() + " " + message + "\r\n", function (err) {
        if (err) throw err;

First I had only "\n" but I noticed that when I open the log file in Notepad, it shows all entries on the same line. Notepad++ on the other hand shows the entries each on their own line. After changing the code to "\r\n", even Notepad shows every entry on its own line.

Redirect stdout to a file in Python?

Based on this answer:, here is another way I figured out which I use in one of my projects. For whatever you replace sys.stderr or sys.stdout with, you have to make sure that the replacement complies with file interface, especially if this is something you are doing because stderr/stdout are used in some other library that is not under your control. That library may be using other methods of file object.

Check out this way where I still let everything go do stderr/stdout (or any file for that matter) and also send the message to a log file using Python's logging facility (but you can really do anything with this):

class FileToLogInterface(file):
    Interface to make sure that everytime anything is written to stderr, it is
    also forwarded to a file.

    def __init__(self, *args, **kwargs):
        if 'cfg' not in kwargs:
            raise TypeError('argument cfg is required.')
            if not isinstance(kwargs['cfg'], config.Config):
                raise TypeError(
                    'argument cfg should be a valid '
                    'PostSegmentation configuration object i.e. '
        self._cfg = kwargs['cfg']

        self._logger = logging.getlogger('access_log')

        super(FileToLogInterface, self).__init__(*args, **kwargs)

    def write(self, msg):
        super(FileToLogInterface, self).write(msg)

pandas python how to count the number of records or rows in a dataframe

To get the number of rows in a dataframe use:


(and df.shape[1] to get the number of columns).

As an alternative you can use




(and len(df.columns) for the columns)

shape is more versatile and more convenient than len(), especially for interactive work (just needs to be added at the end), but len is a bit faster (see also this answer).

To avoid: count() because it returns the number of non-NA/null observations over requested axis

len(df.index) is faster

import pandas as pd
import numpy as np

df = pd.DataFrame(np.arange(24).reshape(8, 3),columns=['A', 'B', 'C'])
# Out:
#     A   B   C
# 0   0   1   2
# 1   3   4   5
# 2   6   7   8
# 3   9  10  11
# 4  12  13  14
# 5 NaN  16  17
# 6  18  19  20
# 7  21  22  23

%timeit df.shape[0]
# 100000 loops, best of 3: 4.22 µs per loop

%timeit len(df)
# 100000 loops, best of 3: 2.26 µs per loop

%timeit len(df.index)
# 1000000 loops, best of 3: 1.46 µs per loop

df.__len__ is just a call to len(df.index)

import inspect 
# Out:
#     def __len__(self):
#         """Returns length of info axis, but here we use the index """
#         return len(self.index)

Why you should not use count()

# Out:
# A    7
# B    8
# C    8

How to use OKHTTP to make a post request?

If you want to post parameter in okhttp as body content which can be encrypted string with content-type as "application/x-www-form-urlencoded" you can first use URLEncoder to encode the data and then use :

final MediaType MEDIA_TYPE_MARKDOWN = MediaType.parse("application/x-www-form-urlencoded");

okhttp3.Request request = new okhttp3.Request.Builder()
    .post(RequestBody.create(MEDIA_TYPE_MARKDOWN, yourBodyDataToPostOnserver))

you can add header according to your requirement.

CSS: Change image src on img:hover

Here is an alternate approach using pure CSS. The idea is to include both the images in the HTML markup and have these displayed or hidden accordingly on :hover


   <img src="" /> 
   <img src="" />


a img:last-child {
  display: none;  
a:hover img:last-child {
  display: block;  
a:hover img:first-child {
  display: none;  


Note that the images used are of the same dimensions for proper display. Also, these images file sizes are quite small so loading multiple is not an issue in this case but may be if you are looking to toggle display of large sized images.

How to allow download of .json file with ASP.NET

Solution is you need to add json file extension type in MIME Types

Method 1

Go to IIS, Select your application and Find MIME Types

enter image description here

Click on Add from Right panel

File Name Extension = .json

MIME Type = application/json

enter image description here

After adding .json file type in MIME Types, Restart IIS and try to access json file

Method 2

Go to web.config of that application and add this lines in it

     <mimeMap fileExtension=".json" mimeType="application/json" />

Setting background colour of Android layout element

4 possible ways, use one you need.

1. Kotlin

val ll = findViewById<LinearLayout>(
ll.setBackgroundColor(ContextCompat.getColor(this, R.color.white))

2. Data Binding


OR more useful statement-


3. XML



4. Java

LinearLayout ll = (LinearLayout) findViewById(;
ll.setBackgroundColor(ContextCompat.getColor(this, R.color.white));

How to write LDAP query to test if user is member of a group?

I would add one more thing to Marc's answer: The memberOf attribute can't contain wildcards, so you can't say something like "memberof=CN=SPS*", and expect it to find all groups that start with "SPS".

What's the bad magic number error?

Loading a python3 generated *.pyc file with python2 also causes this error.

How do I declare a model class in my Angular 2 component using TypeScript?

You can use the angular-cli as the comments in @brendon's answer suggest.

You might also want to try:

ng g class modelsDirectoy/modelName --type=model

/* will create
 +-- modelName.model.ts
 +-- ...

Bear in mind: ng g class !== ng g c
However, you can use ng g cl as shortcut depending on your angular-cli version.

How to set a JVM TimeZone Properly

The accepted answer above:


Didn't work for me exactly. I only was able to successfully change my timezone when I didn't have quotes around the parameters:


Sending XML data using HTTP POST with PHP

you can use cURL library for posting data:

$ch = curl_init();
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_URL, "http://websiteURL");
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "XML=".$xmlcontent."&password=".$password."&etc=etc");

where postfield contains XML you need to send - you will need to name the postfield the API service (Clickatell I guess) expects

UITableview: How to Disable Selection for Some Rows but Not Others

on Xcode 7 without coding you can simply do the following:

In the outline view, select Table View Cell. (The cell is nested under Table View Controller Scene > Table View Controller > Table View. You may have to disclose those objects to see the table view cell)

In the Attributes inspector, find the field labeled Selection and select None. atribute inspector With this option, the cell won’t get a visual highlight when a user taps it.

Where can I find the assembly System.Web.Extensions dll?

I had this problem myself. Most of the information I could find online was related to people having this problem with an ASP.NET web application. I was creating a Win Forms stand alone app so most of the advice wasn't helpful for me.

Turns out that the problem was that my project was set to use the ".NET 4 Framework Client Profile" as the target framework and the System.Web.Extensions reference was not in the list for adding. I changed the target to ".NET 4 Framework" and then the reference was available by the normal methods.

Here is what worked for me step by step:

  1. Right Click you project Select Properties
  2. Change your Target Framework to ".NET Framework 4"
  3. Do whatever you need to do to save the changes and close the preferences tab
  4. Right click on the References item in your Solution Explorer
  5. Choose Add Reference...
  6. In the .NET tab, scroll down to System.Web.Extensions and add it.

How can I check if two segments intersect?

Here is C code to check if two points are on the opposite sides of the line segment. Using this code you can check if two segments intersect as well.

// true if points p1, p2 lie on the opposite sides of segment s1--s2
bool oppositeSide (Point2f s1, Point2f s2, Point2f p1, Point2f p2) {

//calculate normal to the segment
Point2f vec = s1-s2;
Point2f normal(vec.y, -vec.x); // no need to normalize

// vectors to the points
Point2f v1 = p1-s1;
Point2f v2 = p2-s1;

// compare signs of the projections of v1, v2 onto the normal
float proj1 =;
float proj2 =;
if (proj1==0 || proj2==0)
        cout<<"collinear points"<<endl;

return(SIGN(proj1) != SIGN(proj2));


Get element of JS object with an index

var myobj = {"A":["Abe"], "B":["Bob"]};

var keysArray = Object.keys(myobj);

var valuesArray = Object.keys(myobj).map(function(k) {

   return String(myobj[k]);


var mydata = valuesArray[keysArray.indexOf("A")]; // Abe

Send and receive messages through NSNotificationCenter in Objective-C?

To expand upon dreamlax's example... If you want to send data along with the notification

In posting code:

NSDictionary *userInfo = 
[NSDictionary dictionaryWithObject:myObject forKey:@"someKey"];
[[NSNotificationCenter defaultCenter] postNotificationName: 
                       @"TestNotification" object:nil userInfo:userInfo];

In observing code:

- (void) receiveTestNotification:(NSNotification *) notification {

    NSDictionary *userInfo = notification.userInfo;
    MyObject *myObject = [userInfo objectForKey:@"someKey"];

MySQL: Grant **all** privileges on database

GRANT ALL PRIVILEGES ON mydb.* TO myuser@localhost IDENTIFIED BY 'mypasswd';

Works for privileges on schema :)

Optional: after mypasswd you can add WITH GRANT OPTION

How to compare two Carbon Timestamps?

First, Eloquent automatically converts it's timestamps (created_at, updated_at) into carbon objects. You could just use updated_at to get that nice feature, or specify edited_at in your model in the $dates property:

protected $dates = ['edited_at'];

Now back to your actual question. Carbon has a bunch of comparison functions:

  • eq() equals
  • ne() not equals
  • gt() greater than
  • gte() greater than or equals
  • lt() less than
  • lte() less than or equals


    // edited at is newer than created at

Android offline documentation and sample codes

Write the following in linux terminal:

$ wget -r

How to get access to raw resources that I put in res folder?

This worked for for me: getResources().openRawResource(R.raw.certificate)

Visual Studio 2017 - Git failed with a fatal error

I also had this issue after I got wget from the GNU tools, and copied it right into c:\windows. The libeay.dll and libssl.dll files were also in the archive. When those were in c:\windows, I had this issue. Removing them immediately fixed it. So, check if you have these .DLLs somewhere in your path, VS may be picking up some other software's version of these instead of using the ones it expects.

Labeling file upload button

You get your browser's language for your button. There's no way to change it programmatically.

How to split a line into words separated by one or more spaces in bash?

echo $line | tr " " "\n"

gives the output similar to those of most of the answers above; without using loops.

In your case, you also mention ll=<...output...>,
so, (given that I don't know much python and assuming you need to assign output to a variable),

ll=`echo $line | tr " " "\n"`

should suffice (remember to echo "$ll" instead of echo $ll)

Determine if Python is running inside virtualenv

There are a lot of great methods posted here already, but just adding one more:

import site

tells you where pip installed the packages.

How to pick a new color for each plotted line within a figure in matplotlib?

As Ciro's answer notes, you can use prop_cycle to set a list of colors for matplotlib to cycle through. But how many colors? What if you want to use the same color cycle for lots of plots, with different numbers of lines?

One tactic would be to use a formula like the one from, to generate an infinite sequence of colors where each color tries to be significantly different from all those that preceded it.

Unfortunately, prop_cycle won't accept infinite sequences - it will hang forever if you pass it one. But we can take, say, the first 1000 colors generated from such a sequence, and set it as the color cycle. That way, for plots with any sane number of lines, you should get distinguishable colors.


from matplotlib import pyplot as plt
from matplotlib.colors import hsv_to_rgb
from cycler import cycler

# 1000 distinct colors:
colors = [hsv_to_rgb([(i * 0.618033988749895) % 1.0, 1, 1])
          for i in range(1000)]
plt.rc('axes', prop_cycle=(cycler('color', colors)))

for i in range(20):
    plt.plot([1, 0], [i, i])


Graph output by the code above

Now, all the colors are different - although I admit that I struggle to distinguish a few of them!

SelectedValue vs SelectedItem.Value of DropDownList

SelectedValue returns the same value as SelectedItem.Value.

SelectedItem.Value and SelectedItem.Text might have different values and the performance is not a factor here, only the meanings of these properties matters.

<asp:DropDownList runat="server" ID="ddlUserTypes">
    <asp:ListItem Text="Admins" Value="1" Selected="true" />
    <asp:ListItem Text="Users" Value="2"/>

Here, ddlUserTypes.SelectedItem.Value == ddlUserTypes.SelectedValue and both would return the value "1".

ddlUserTypes.SelectedItem.Text would return "Admins", which is different from ddlUserTypes.SelectedValue


under the hood, SelectedValue looks like this

public virtual string SelectedValue
        int selectedIndex = this.SelectedIndex;
        if (selectedIndex >= 0)
            return this.Items[selectedIndex].Value;
        return string.Empty;

and SelectedItem looks like this:

public virtual ListItem SelectedItem
        int selectedIndex = this.SelectedIndex;
        if (selectedIndex >= 0)
            return this.Items[selectedIndex];
        return null;

One major difference between these two properties is that the SelectedValue has a setter also, since SelectedItem doesn't. The getter of SelectedValue is faster when writing code, and the problem of execution performance has no real reason to be discussed. Also a big advantage of SelectedValue is when using Binding expressions.

edit data binding scenario (you can't use SelectedItem.Value)

<asp:Repeater runat="server">
     <asp:DropDownList ID="ddlCategories" runat="server" 
                       SelectedValue='<%# Eval("CategoryId")%>'>

How do I launch the Android emulator from the command line?

Just to add here, whenever you get "error: device offline" means that connection with emulator & adb bridge has been broken due to time taken in emulator startup.

Rather than re-starting emulator at this point try below two commands which stops & start adb bridge again.

adb kill-server

adb start-server


your can try this :

SELECT columnName1, CAST(columnName2 AS  SIGNED ) FROM tableName 

Java: Integer equals vs. ==

You can't compare two Integer with a simple == they're objects so most of the time references won't be the same.

There is a trick, with Integer between -128 and 127, references will be the same as autoboxing uses Integer.valueOf() which caches small integers.

If the value p being boxed is true, false, a byte, a char in the range \u0000 to \u007f, or an int or short number between -128 and 127, then let r1 and r2 be the results of any two boxing conversions of p. It is always the case that r1 == r2.

Resources :

On the same topic :

how can I enable PHP Extension intl?

For Megento Installation you Need to

  1. Stop Apache Service
  2. uncomment the extension=php_intl.dll in php.ini file.
  3. copy all 6 files icudt57.dll,icuin57.dll,icuio57.dll,icule57.dll,iculx57.dll,icuuc57.dll From php folder to apache\bin Now Restart you apache service

Reading HTML content from a UIWebView


get HTML from UIWebView`

let content = uiWebView.stringByEvaluatingJavaScript(from: "document.body.innerHTML")

set HTML into UIWebView

//Do not forget to extend a class from `UIWebViewDelegate` and nil the delegate

func someFunction() {

    let uiWebView = UIWebView()
    uiWebView.loadHTMLString("<html><body></body></html>", baseURL: nil)
    uiWebView.delegate = self as? UIWebViewDelegate

func webViewDidFinishLoad(_ webView: UIWebView) {
    //ready to be processed

[get/set HTML from WKWebView]

What is the meaning of "int(a[::-1])" in Python?

The notation that is used in


means that for a given string/list/tuple, you can slice the said object using the format

<object_name>[<start_index>, <stop_index>, <step>]

This means that the object is going to slice every "step" index from the given start index, till the stop index (excluding the stop index) and return it to you.

In case the start index or stop index is missing, it takes up the default value as the start index and stop index of the given string/list/tuple. If the step is left blank, then it takes the default value of 1 i.e it goes through each index.


a = '1234'
print a[::2]

would print


Now the indexing here and also the step count, support negative numbers. So, if you give a -1 index, it translates to len(a)-1 index. And if you give -x as the step count, then it would step every x'th value from the start index, till the stop index in the reverse direction. For example

a = '1234'
print a[3:0:-1]

This would return


Note, that it doesn't return 4321 because, the stop index is not included.

Now in your case,


would just reverse a given integer, that is stored in a string, and then convert it back to a string

i.e "1234" -> "4321" -> 4321 -> "4321"

If what you are trying to do is just reverse the given string, then simply a[::-1] would work .

img tag displays wrong orientation

This answer builds on bsap's answer using Exif-JS , but doesn't rely on jQuery and is fairly compatible even with older browsers. The following are example html and js files:


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN"
      .rotate90 {
       -webkit-transform: rotate(90deg);
       -moz-transform: rotate(90deg);
       -o-transform: rotate(90deg);
       -ms-transform: rotate(90deg);
       transform: rotate(90deg);
      .rotate180 {
       -webkit-transform: rotate(180deg);
       -moz-transform: rotate(180deg);
       -o-transform: rotate(180deg);
       -ms-transform: rotate(180deg);
       transform: rotate(180deg);
      .rotate270 {
       -webkit-transform: rotate(270deg);
       -moz-transform: rotate(270deg);
       -o-transform: rotate(270deg);
       -ms-transform: rotate(270deg);
       transform: rotate(270deg);
    <img src="pic/pic03.jpg" width="200" alt="Cat 1" id="campic" class="camview">
    <script type="text/javascript" src="exif.js"></script>
    <script type="text/javascript" src="rotate.js"></script>


var newimg = document.getElementById('campic');
function getExif() {
    EXIF.getData(newimg, function() {
            var orientation = EXIF.getTag(this, "Orientation");
            if(orientation == 6) {
                newimg.className = "camview rotate90";
            } else if(orientation == 8) {
                newimg.className = "camview rotate270";
            } else if(orientation == 3) {
                newimg.className = "camview rotate180";

node.js - how to write an array to file

Remember you can access good old ECMAScript APIs, in this case, JSON.stringify().

For simple arrays like the one in your example:




    function (err) {
        if (err) {
            console.error('Crap happens');

Does Django scale?

I develop high traffic sites using Django for the national broadcaster in Ireland. It works well for us. Developing a high performance site is more than about just choosing a framework. A framework will only be one part of a system that is as strong as it's weakest link. Using the latest framework 'X' won't solve your performance issues if the problem is slow database queries or a badly configured server or network.

How to find a whole word in a String in java

You can also use regex matching with the \b flag (whole word boundary).

PHP foreach with Nested Array?

Both syntaxes are correct. But the result would be Array. You probably want to do something like this:

foreach ($tmpArray[1] as $value) {
  echo $value[0];
  foreach($value[1] as $val){
    echo $val;

This will print out the string "two" ($value[0]) and the integers 4, 5 and 6 from the array ($value[1]).

ClientAbortException: Connection reset by peer: socket write error

Windows Firewall could cause this exception, try to disable it or add a rule for port or even program (java)

Python: finding lowest integer

number_list = [99.5,1.2,-0.3]


print number_list[0]

Custom header to HttpClient request

var request = new HttpRequestMessage {
    RequestUri = new Uri("[your request url string]"),
    Method = HttpMethod.Post,
    Headers = {
        { "X-Version", "1" } // HERE IS HOW TO ADD HEADERS,
        { HttpRequestHeader.Authorization.ToString(), "[your authorization token]" },
        { HttpRequestHeader.ContentType.ToString(), "multipart/mixed" },//use this content type if you want to send more than one content type
    Content = new MultipartContent { // Just example of request sending multipart request
        new ObjectContent<[YOUR JSON OBJECT TYPE]>(
            new [YOUR JSON OBJECT TYPE INSTANCE](...){...}, 
            new JsonMediaTypeFormatter(), 
            "application/json"), // this will add 'Content-Type' header for the first part of request
        new ByteArrayContent([BINARY DATA]) {
            Headers = { // this will add headers for the second part of request
                { "Content-Type", "application/Executable" },
                { "Content-Disposition", "form-data; filename=\"test.pdf\"" },

Difference between Convert.ToString() and .ToString()

Convert.ToString(value) first tries casting obj to IConvertible, then IFormattable to call corresponding ToString(...) methods. If instead the parameter value was null then return string.Empty. As a last resort, return obj.ToString() if nothing else worked.

It's worth noting that Convert.ToString(value) can return null if for example value.ToString() returns null.

See .Net reference source

Running Groovy script from the command line

sed '1,2d' "$0"|$(which groovy) /dev/stdin; exit;


Explicitly select items from a list or tuple

like often when you have a boolean numpy array like mask

[mylist[i] for i in np.arange(len(mask), dtype=int)[mask]]

A lambda that works for any sequence or np.array:

subseq = lambda myseq, mask : [myseq[i] for i in np.arange(len(mask), dtype=int)[mask]]

newseq = subseq(myseq, mask)

Generic Interface

I'd stay with two different interfaces.

You said that 'I want to group my service executors under a common interface... It also seems overkill creating two separate interfaces for the two different service calls... A class will only implement one of these interfaces'

It's not clear what is the reason to have a single interface then. If you want to use it as a marker, you can just exploit annotations instead.

Another point is that there is a possible case that your requirements change and method(s) with another signature appears at the interface. Of course it's possible to use Adapter pattern then but it would be rather strange to see that particular class implements interface with, say, three methods where two of them trow UnsupportedOperationException. It's possible that the forth method appears etc.

Forward slash in Java Regex

The problem is actually that you need to double-escape backslashes in the replacement string. You see, "\\/" (as I'm sure you know) means the replacement string is \/, and (as you probably don't know) the replacement string \/ actually just inserts /, because Java is weird, and gives \ a special meaning in the replacement string. (It's supposedly so that \$ will be a literal dollar sign, but I think the real reason is that they wanted to mess with people. Other languages don't do it this way.) So you have to write either:

"Hello/You/There".replaceAll("/", "\\\\/");


"Hello/You/There".replaceAll("/", Matcher.quoteReplacement("\\/"));

(Using java.util.regex.Matcher.quoteReplacement(String).)

Regex pattern to match at least 1 number and 1 character in a string

Maybe a bit late, but this is my RE:



\w* -> 0 or more alphanumeric digits, at the beginning

\d+[a-zA-Z]|[a-zA-Z]+\d -> a digit + a letter OR a letter + a digit

\w* -> 0 or more alphanumeric digits, again

I hope it was understandable

Python TypeError: not enough arguments for format string

You need to put the format arguments into a tuple (add parentheses):

instr = "'%s', '%s', '%d', '%s', '%s', '%s', '%s'" % (softname, procversion, int(percent), exe, description, company, procurl)

What you currently have is equivalent to the following:

intstr = ("'%s', '%s', '%d', '%s', '%s', '%s', '%s'" % softname), procversion, int(percent), exe, description, company, procurl


>>> "%s %s" % 'hello', 'world'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: not enough arguments for format string
>>> "%s %s" % ('hello', 'world')
'hello world'

What is the max size of localStorage values?

You can use the following code in modern browsers to efficiently check the storage quota (total & used) in real-time:

if ('storage' in navigator && 'estimate' in {
            .then(estimate => {
                console.log("Usage (in Bytes): ", estimate.usage,
                            ",  Total Quota (in Bytes): ", estimate.quota);

In Gradle, is there a better way to get Environment Variables?

Well; this works as well:

home = "$System.env.HOME"

It's not clear what you're aiming for.

Drawable image on a canvas


import android.content.Context;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class SurafaceClass extends SurfaceView implements
        SurfaceHolder.Callback {
    Bitmap mBitmap;
Paint paint =new Paint();
    public SurafaceClass(Context context) {
        mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.icon);
        // TODO Auto-generated constructor stub

    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        // TODO Auto-generated method stub


    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub


    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub


    protected void onDraw(Canvas canvas) {
        canvas.drawBitmap(mBitmap, 0, 0, paint);



Nginx location "not equal to" regex

i was looking for the same. and found this solution.

Use negative regex assertion:

location ~ ^/(?!(favicon\.ico|resources|robots\.txt)) { 
.... # your stuff 

Source Negated Regular Expressions in location

Explanation of Regex :

If URL does not match any of the following path

Then it will go inside that location block and will process it.

How do I add a newline using printf?

To write a newline use \n not /n the latter is just a slash and a n

macro for Hide rows in excel 2010

You almost got it. You are hiding the rows within the active sheet. which is okay. But a better way would be add where it is.

Rows("52:55").EntireRow.Hidden = False


activesheet.Rows("52:55").EntireRow.Hidden = False

i've had weird things happen without it. As for making it automatic. You need to use the worksheet_change event within the sheet's macro in the VBA editor (not modules, double click the sheet1 to the far left of the editor.) Within that sheet, use the drop down menu just above the editor itself (there should be 2 listboxes). The listbox to the left will have the events you are looking for. After that just throw in the macro. It should look like the below code,

Private Sub Worksheet_Change(ByVal Target As Range)
end Sub

That's it. Anytime you change something, it will run the macro test1.

SQL: IF clause within WHERE clause

Use a CASE statement instead of IF.

Java 8 stream's .min() and .max(): why does this compile?

Apart from the information given by David M. Lloyd one could add that the mechanism that allows this is called target typing.

The idea is that the type the compiler assigns to a lambda expressions or a method references does not depend only on the expression itself, but also on where it is used.

The target of an expression is the variable to which its result is assigned or the parameter to which its result is passed.

Lambda expressions and method references are assigned a type which matches the type of their target, if such a type can be found.

See the Type Inference section in the Java Tutorial for more information.

Cannot connect to MySQL 4.1+ using old authentication

If you do not have control of the server

I just had this issue, and was able to work around it.

First, connect to the MySQL database with an older client that doesn't mind old_passwords. Connect using the user that your script will be using.

Run these queries:

SET SESSION old_passwords=FALSE;
SET PASSWORD = PASSWORD('[your password]');

In your PHP script, change your mysql_connect function to include the client flag 1:

mysql_connect('[your server]', '[your username]', '[your password]', false, CLIENT_LONG_PASSWORD);

This allowed me to connect successfully.

Edit: as per Garland Pope's comment, it may not be necessary to set CLIENT_LONG_PASSWORD manually any more in your PHP code as of PHP 5.4!

Edit: courtesy of Antonio Bonifati, a PHP script to run the queries for you:

<?php const DB = [ 'host' => '...', # localhost may not work on some hosting 
    'user' => '...',
    'pwd' => '...', ]; 

if (!mysql_connect(DB['host'], DB['user'], DB['pwd'])) {
} if (!mysql_query($query = 'SET SESSION old_passwords=FALSE')) {
} if (!mysql_query($query = "SET PASSWORD = PASSWORD('" . DB['pwd'] . "')")) {

echo "Excellent, mysqli will now work"; 

Increment a database field by 1

You didn't say what you're trying to do, but you hinted at it well enough in the comments to the other answer. I think you're probably looking for an auto increment column

create table logins (userid int auto_increment primary key, 
  username varchar(30), password varchar(30));

then no special code is needed on insert. Just

insert into logins (username, password) values ('user','pass');

The MySQL API has functions to tell you what userid was created when you execute this statement in client code.

OS X Sprite Kit Game Optimal Default Window Size

You should target the smallest, not the largest, supported pixel resolution by the devices your app can run on.

Say if there's an actual Mac computer that can run OS X 10.9 and has a native screen resolution of only 1280x720 then that's the resolution you should focus on. Any higher and your game won't correctly run on this device and you could as well remove that device from your supported devices list.

You can rely on upscaling to match larger screen sizes, but you can't rely on downscaling to preserve possibly important image details such as text or smaller game objects.

The next most important step is to pick a fitting aspect ratio, be it 4:3 or 16:9 or 16:10, that ideally is the native aspect ratio on most of the supported devices. Make sure your game only scales to fit on devices with a different aspect ratio.

You could scale to fill but then you must ensure that on all devices the cropped areas will not negatively impact gameplay or the use of the app in general (ie text or buttons outside the visible screen area). This will be harder to test as you'd actually have to have one of those devices or create a custom build that crops the view accordingly.

Alternatively you can design multiple versions of your game for specific and very common screen resolutions to provide the best game experience from 13" through 27" displays. Optimized designs for iMac (desktop) and a Macbook (notebook) devices make the most sense, it'll be harder to justify making optimized versions for 13" and 15" plus 21" and 27" screens.

But of course this depends a lot on the game. For example a tile-based world game could simply provide a larger viewing area onto the world on larger screen resolutions rather than scaling the view up. Provided that this does not alter gameplay, like giving the player an unfair advantage (specifically in multiplayer).

You should provide @2x images for the Retina Macbook Pro and future Retina Macs.

Input type number "only numeric value" validation

In HTML file you can add ngIf for you pattern like this

<div class="form-control-feedback" *ngIf="Mobile.errors && (Mobile.dirty || Mobile.touched)">
        <p *ngIf="Mobile.errors.pattern" class="text-danger">Number Only</p>

In .ts file you can add the Validators pattern - "^[0-9]*$"

this.Mobile = new FormControl('', [

phpexcel to download

Instead of saving it to a file, save it to php://output­Docs:


This will send it AS-IS to the browser.

You want to add some headers­Docs first, like it's common with file downloads, so the browser knows which type that file is and how it should be named (the filename):

// We'll be outputting an excel file
header('Content-type: application/');

// It will be called file.xls
header('Content-Disposition: attachment; filename="file.xls"');

// Write file to the browser

First do the headers, then the save. For the excel headers see as well the following question: Setting mime type for excel document.

How To Get Selected Value From UIPickerView

This is my answer

- (IBAction)Result:(id)sender 
   self.statusLabel.text = DataSource[[pickerViewTool selectedRowInComponent:0]];


m2eclipse not finding maven dependencies, artifacts not found

One of the reason I found was why it doesn't find a jar from repository might be because the .pom file for that particular jar might be missing or corrupt. Just correct it and try to load from local repository.

What datatype should be used for storing phone numbers in SQL Server 2005?

It is always better to have separate tables for multi valued attributes like phone number.

As you have no control on source data so, you can parse the data from XML file and convert it into the proper format so that there will not be any issue with formats of a particular country and store it in a separate table so that indexing and retrieval both will be efficient.

Thank you.

How to show/hide an element on checkbox checked/unchecked states using jQuery?

    <label  onclick="chkBulk();">
    <div class="icheckbox_flat-green" style="position: relative;">
      <asp:CheckBox ID="chkBulkAssign" runat="server" class="flat" 
         absolute; opacity: 0;" />
      Bulk Assign

    function chkBulk() {
    if ($('[id$=chkBulkAssign]')[0].checked) {
    $('div .icheckbox_flat-green').addClass('checked');
   else {
   $('div .icheckbox_flat-green').removeClass('checked');

How can I parse a local JSON file from assets folder into a ListView?

With Kotlin have this extension function to read the file return as string.

fun AssetManager.readAssetsFile(fileName : String): String = open(fileName).bufferedReader().use{it.readText()}

Parse the output string using any JSON parser.

android pick images from gallery

Here is a full example for request permission (if need), pick image from gallery, then convert image to bitmap or file


<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>


class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {

        button_pick_image.setOnClickListener {

    private fun pickImage() {
        if (ActivityCompat.checkSelfPermission(this, READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
            val intent = Intent(
            intent.type = "image/*"
            intent.putExtra("crop", "true")
            intent.putExtra("scale", true)
            intent.putExtra("aspectX", 16)
            intent.putExtra("aspectY", 9)
            startActivityForResult(intent, PICK_IMAGE_REQUEST_CODE)
        } else {

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        if (requestCode == PICK_IMAGE_REQUEST_CODE) {
            if (resultCode != Activity.RESULT_OK) {
            val uri = data?.data
            if (uri != null) {
                val imageFile = uriToImageFile(uri)
                // todo do something with file
            if (uri != null) {
                val imageBitmap = uriToBitmap(uri)
                // todo do something with bitmap

    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        when (requestCode) {
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    // pick image after request permission success

    private fun uriToImageFile(uri: Uri): File? {
        val filePathColumn = arrayOf(MediaStore.Images.Media.DATA)
        val cursor = contentResolver.query(uri, filePathColumn, null, null, null)
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                val columnIndex = cursor.getColumnIndex(filePathColumn[0])
                val filePath = cursor.getString(columnIndex)
                return File(filePath)
        return null

    private fun uriToBitmap(uri: Uri): Bitmap {
        return MediaStore.Images.Media.getBitmap(this.contentResolver, uri)

    companion object {
        const val PICK_IMAGE_REQUEST_CODE = 1000


The I/O operation has been aborted because of either a thread exit or an application request

I had the same issue with RS232 communication. The reason, is that your program executes much faster than the comport (or slow serial communication).

To fix it, I had to check if the IAsyncResult.IsCompleted==true. If not completed, then IAsyncResult.AsyncWaitHandle.WaitOne()

Like this :

Stream s = this.GetStream();
IAsyncResult ar = s.BeginWrite(data, 0, data.Length, SendAsync, state);
if (!ar.IsCompleted)

Most of the time, ar.IsCompleted will be true.

Set Matplotlib colorbar size to match graph

You can do this easily with a matplotlib AxisDivider.

The example from the linked page also works without using subplots:

import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable
import numpy as np

ax = plt.gca()
im = ax.imshow(np.arange(100).reshape((10,10)))

# create an axes on the right side of ax. The width of cax will be 5%
# of ax and the padding between cax and ax will be fixed at 0.05 inch.
divider = make_axes_locatable(ax)
cax = divider.append_axes("right", size="5%", pad=0.05)

plt.colorbar(im, cax=cax)

enter image description here

'cannot open git-upload-pack' error in Eclipse when cloning or pushing git repository

I'm using Eclipse Kepler SR2 on Ubuntu 12.04LTS and was trying to access an internal GitHub using HTTPS. Unfortunately, my underlying JVM with which Eclipse was started experienced problems with the self-signed certificate of the server. Switching to a different JVM for Eclipse got the HTTPS connection to our GitHub working.

Create a simple Eclipse starter that uses a different JDK, e.g. with OpenJDK: /Eclipse_Kepler_4.4.2/eclipse -vm /usr/lib/jvm/java-6-openjdk-i386/jre/bin

Logging best practices

What frameworks do you use?

We use a mix of the logging application block, and a custom logging helper that works around the .Net framework bits. The LAB is configured to output fairly extensive log files included seperate general trace files for service method entry/exit and specific error files for unexpected issues. The configuration includes date/time, thread, pId etc. for debug assistance as well as the full exception detail and stack (in the case of an unexpected exception).

The custom logging helper makes use of the Trace.Correlation and is particularly handy in the context of logging in WF. For example we have a state machine that invokes a series of sequential workflows. At each of these invoke activities we log the start (using StartLogicalOperation) and then at the end we stop the logical operation with a gereric return event handler.

This has proven useful a few times when attempting to debug failures in complex business sequences as it allows us to determine things like If/Else branch decisions etc. more quickly based on the activity execution sequence.

What log outputs do you use?

We use text files and XML files. Text files are configured through the app block but we've got XML outputs as well from our WF service. This enables us to capture the runtime events (persistence etc.) as well as generic business type exceptions. The text files are rolling logs that are rolled by day and size (I believe total size of 1MB is a rollover point).

What tools to you use for viewing the logs?

We are using Notepad and WCF Service Trace Viewer depending on which output group we're looking at. The WCF Service Trace Viewer is really really handy if you've got your output setup correctly and can make reading the output much simpler. That said, if I know roughly where the error is anyway - just reading a well annotated text file is good as well.

The logs are sent to a single directory which is then split into sub-dirs based on the source service. The root dir is exposed via a website which has it's access controlled by a support user group. This allows us to take a look at production logs without having to put in requests and go through lengthy red tape processes for production data.

Remove all items from RecyclerView

public void clearData() {

Decreasing for loops in Python impossible?

for n in range(6,0,-1):
    print n

Remove an item from an IEnumerable<T> collection

Try turning the IEnumerable into a List. From this point on you will be able to use List's Remove method to remove items.

To pass it as a param to the Remove method using Linq you can get the item by the following methods:

  • users.Single(x => x.userId == 1123)
  • users.First(x => x.userId == 1123)

The code is as follows:

users = users.ToList(); // Get IEnumerable as List

users.Remove(users.First(x => x.userId == 1123)); // Remove item

// Finished

AngularJS HTTP post to PHP and undefined

It's an old question but it worth to mention that in Angular 1.4 $httpParamSerializer is added and when using $, if we use $httpParamSerializer(params) to pass the parameters, everything works like a regular post request and no JSON deserializing is needed on server side.$httpParamSerializer

How to programmatically set SelectedValue of Dropdownlist when it is bound to XmlDataSource

This is working code

protected void Page_Load(object sender, EventArgs e)
            if (!Page.IsPostBack)
                    DropDownList1.DataTextField = "user_name";
                    DropDownList1.DataValueField = "user_id";
                    DropDownList1.DataSource = getData();// get the data into the list you can set it

    DropDownList1.SelectedIndex = DropDownList1.Items.IndexOf(DropDownList1.Items.FindByText("your default selected text"));


You did the right thing by checking from query plans. But I have 100% confidence in version 2. It is faster when the number off records are on the very high side.

My database has around 1,000,000 records and this is exactly the scenario where the query plan shows the difference between both the queries. Further, instead of using a where clause, if you use it in the join itself, it makes the query faster :
SELECT p.Name, s.OrderQty
FROM Product p
INNER JOIN (SELECT ProductID, OrderQty FROM SalesOrderDetail) s on p.ProductID = s.ProductID WHERE p.isactive = 1

The better version of this query is :

SELECT p.Name, s.OrderQty
FROM Product p
INNER JOIN (SELECT ProductID, OrderQty FROM SalesOrderDetail) s on p.ProductID = s.ProductID AND p.isactive = 1

(Assuming isactive is a field in product table which represents the active/inactive products).

Comparison of DES, Triple DES, AES, blowfish encryption for data

Although TripleDESCryptoServiceProvider is a safe and good method but it's too slow. If you want to refer to MSDN you will get that advise you to use AES rather TripleDES. Please check below link: you will see this attention in the remark section:

Note A newer symmetric encryption algorithm, Advanced Encryption Standard (AES), is available. Consider using the AesCryptoServiceProvider class instead of the TripleDESCryptoServiceProvider class. Use TripleDESCryptoServiceProvider only for compatibility with legacy applications and data.

Good luck

Combining multiple condition in single case statement in Sql Server

You can put the condition after the WHEN clause, like so:

    WHEN PAT_ENT.SCR_DT is not null and PAT_ENTRY.ELIGIBILITY is null THEN 'Favor'
    WHEN PAT_ENT.SCR_DT is not null and PAT_ENTRY.EL = 'No' THEN 'Error'
    WHEN PAT_ENTRY.EL = 'Yes' and ISNULL(DS.DES, 'OFF') = 'OFF' THEN 'Active'
    WHEN DS.DES = 'N' THEN 'Early Term'
    WHEN DS.DES = 'Y' THEN 'Complete'

Of course, the argument could be made that complex rules like this belong in your business logic layer, not in a stored procedure in the database...

chrome undo the action of "prevent this page from creating additional dialogs"

If you wish dialog box to be re-activated for the page you set as prevent dialog box to show.

Chrome: select settings, a google page for chrome will open with all your settings for chrome.

At the very bottom, go to advance settings and at the bottom of the advance settings you may click on Resset Browser Settings... this will make dialog box appear as they should.

How to read a single character from the user?

The ActiveState's recipe seems to contain a little bug for "posix" systems that prevents Ctrl-C from interrupting (I'm using Mac). If I put the following code in my script:


I will never be able to terminate the script with Ctrl-C, and I have to kill my terminal to escape.

I believe the following line is the cause, and it's also too brutal:


Asides from that, package tty is not really needed, termios is enough to handle it.

Below is the improved code that works for me (Ctrl-C will interrupt), with the extra getche function that echo the char as you type:

if sys.platform == 'win32':
    import msvcrt
    getch = msvcrt.getch
    getche = msvcrt.getche
    import sys
    import termios
    def __gen_ch_getter(echo):
        def __fun():
            fd = sys.stdin.fileno()
            oldattr = termios.tcgetattr(fd)
            newattr = oldattr[:]
                if echo:
                    # disable ctrl character printing, otherwise, backspace will be printed as "^?"
                    lflag = ~(termios.ICANON | termios.ECHOCTL)
                    lflag = ~(termios.ICANON | termios.ECHO)
                newattr[3] &= lflag
                termios.tcsetattr(fd, termios.TCSADRAIN, newattr)
                ch =
                if echo and ord(ch) == 127: # backspace
                    # emulate backspace erasing
                    sys.stdout.write('\b \b')
                termios.tcsetattr(fd, termios.TCSADRAIN, oldattr)
            return ch
        return __fun
    getch = __gen_ch_getter(False)
    getche = __gen_ch_getter(True)


Python Traceback (most recent call last)

In Python2, input is evaluated, input() is equivalent to eval(raw_input()). When you enter klj, Python tries to evaluate that name and raises an error because that name is not defined.

Use raw_input to get a string from the user in Python2.

Demo 1: klj is not defined:

>>> input()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1, in <module>
NameError: name 'klj' is not defined

Demo 2: klj is defined:

>>> klj = 'hi'
>>> input()

Demo 3: getting a string with raw_input:

>>> raw_input()

Python pandas insert list into a cell

Also getting

ValueError: Must have equal len keys and value when setting with an iterable,

using .at rather than .loc did not make any difference in my case, but enforcing the datatype of the dataframe column did the trick:

df['B'] = df['B'].astype(object)

Then I could set lists, numpy array and all sorts of things as single cell values in my dataframes.

Add context path to Spring Boot application

If you use Spring Boot 2.0.0 use:


How do I enable TODO/FIXME/XXX task tags in Eclipse?

For me, such tags are enabled by default. You can configure which task tags should be used in the workspace options: Java > Compiler > Task tags

alt text

Check if they are enabled in this location, and that should be enough to have them appear in the Task list (or the Markers view).

Extra note: reinstalling Eclipse won't change anything most of the time if you work on the same workspace. Most settings used by Eclipse are stored in the .metadata folder, in your workspace folder.

How to get temporary folder for current user



Angular - POST uploaded file

In my project , I use the XMLHttpRequest to send multipart/form-data. I think it will fit you to.

and the uploader code

let xhr = new XMLHttpRequest();'POST', '', true);
xhr.withCredentials = true;

Here is example :

What is null in Java?

An interesting way to see null in java in my opinion is to see it as something that DOES NOT denote an absence of information but simply as a literal value that can be assigned to a reference of any type. If you think about it if it denoted absence of information then for a1==a2 to be true doesn't make sense (in case they were both assigned a value of null) as they could really could be pointing to ANY object (we simply don't know what objects they should be pointing to)... By the way null == null returns true in java. If java e.g. would be like SQL:1999 then null==null would return unknown (a boolean value in SQL:1999 can take three values : true,false and unknown but in practise unknown is implemented as null in real systems)...

How to filter an array of objects based on values in an inner array with jq?

Here is another solution which uses any/2

map(select(any(.Names[]; contains("data"))|not)|.Id)[]

with the sample data and the -r option it produces


How do I run Selenium in Xvfb?

The easiest way is probably to use xvfb-run:

DISPLAY=:1 xvfb-run java -jar selenium-server-standalone-2.0b3.jar

xvfb-run does the whole X authority dance for you, give it a try!

I want to get the type of a variable at runtime

If by the type of a variable you mean the runtime class of the object that the variable points to, then you can get this through the class reference that all objects have.

val name = "sam";
name: java.lang.String = sam
res0: java.lang.Class[_] = class java.lang.String

If you however mean the type that the variable was declared as, then you cannot get that. Eg, if you say

val name: Object = "sam"

then you will still get a String back from the above code.